LAC COVID-19 TESTING SERIES Guidebook for Effective National Testing and Surveillance Strategies for SARS-CoV-2: Latin America and the Caribbean Guidebook for January 2023 Effective National Jonathon R. Campbell Testing and Timothy G. Evans Doug Manuel Surveillance Strategies Maura J. Alvarez Baumgartner Amy Zierler for SARS-CoV-2: Aakash Mohpal Jeremy Veillard Latin America and the Caribbean © 2023 International Bank for Reconstruction and Development / The World Bank 1818 H Street NW, Washington DC 20433 Telephone: 202-473-1000; Internet: www.worldbank.org Report No: AUS0002770 Some rights reserved This work is a product of the staff of The World Bank with external contri- butions. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent. 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Latin America and the Caribbean have been hit hard by the COVID-19 pandemic, which continues to undo years of progress on health and human capital in the region. As of December 1, 2022, over 78 million cases of COVID-19 have been diagnosed and over 1.7 million deaths have occurred in the region. As SARS-CoV-2 transmission continues throughout the region, testing capacity—and thus the ability to perform comprehensive surveillance— has failed to increase along with it. Over the past year, CASES (PER MILLION) the omicron variant and its subvariants have laid bare ≥300,000 125,000 to <300,000 these shortcomings, straining testing and health care 15,000 to <125,000 <15,000 systems, and threatening human activity in the region. No data IBRD 46349 | As our experience and understanding of SARS-CoV-2 DECEMBER 2022 have evolved, it is clear we will need to prevent and control SARS-CoV-2 for years to come. Comprehensive, national, public health strategies will therefore be required to protect vulnerable populations and human capital, keep economies open, and minimize the social impacts of SARS-CoV-2, future pandemics, and other public health threats. DEATHS (PER MILLION) ≥ 2,000 1,000 to < 2,000 100 to <1,000 <100 No data IBRD 46350 | DECEMBER 2022 Executive Summary Full Report Executive Summary Key Reasons for National Testing and Surveillance Investing in testing and surveillance systems is We need to stay ahead of Symptom-based testing future waves of infection. alone is insufficient. essential—for the immediate response to SARS- CoV-2 and to prepare for the next public health Why? threat. Developing and implementing effective Inequities will continue national testing and surveillance strategies for Variants of concern to persist with a passive SARS-CoV-2 and proactively leveraging the continue to emerge. approach to SARS-CoV-2 resultant data to inform public health responses must be a key part of national strategies. What Do Effective, National Surveillance Activities for SARS-CoV-2 Provide? Vital data Population-level testing and surveillance are an Activities testing and underappreciated but vital component of national surveillance helps support: strategic plans. These activities produce data to inform where to direct scarce health resources, identify areas of transmission, detect variants, and monitor population health indicators. In short, population-level testing and surveillance can bring indispensable value to the public health response. Directing scarce Monitoring health resources indicators Identifying areas Detecting of transmission variants Executive Summary Full Report Executive Summary Case Examples In this guidebook, a series of case examples highlight real-world experience with testing and surveillance approaches in this global pandemic. These case examples demonstrate the value of designing, implementing, and evaluating testing and surveillance strategies and how they can be leveraged as an essential support for proactive, evidence-based decision-making in the ongoing prevention and control of SARS-CoV-2. Strategic, systematic planning and action on testing capabilities at a national level will put countries in a stronger position not only for the ongoing challenges of SARS-CoV-2 but for other public health emergencies over time. Representative Population Surveys in the United Kingdom Implemented in the first few months of the COVID-19 pandemic, representative household surveys for current and previous SARS-CoV-2 infection continue to be conducted throughout the UK. Supported by collaboration between public, private, and academic sectors, such surveys have been used to identify populations at increased risk of infection and have been used for modeling, supporting proactive—rather than reactive—decision-making. Photo credit: Tim Dennell Population-Wide Antigen Testing in Slovakia In response to rising cases identified through clinical testing, Slovakia enacted public health measures and initiated population-wide antigen testing, with isolation of people testing positive and their contacts. Following the initial wave of testing, a second wave of population-wide testing was targeted to high-prevalence counties. Subsequent epidemio- logic analysis suggested the combination of interventions led to an estimated 82 percent reduction in SARS-CoV-2 prevalence, providing critical information for the public health response moving forward. Photo credit: Joel Bradford Wastewater-Based Surveillance in the Netherlands The city of Rotterdam evaluated the correlation of wastewater-based surveillance with clinical testing data, concluding that wastewater-based surveillance worked as an early warning system, identifying surges six days before clinical testing could. Proactively leveraging this information, the city increased clinical testing, successfully narrowing this detection delay to only 1.5 days. Photo credit: Pouw Vervoer Executive Summary Full Report Executive Summary Case Examples Genomic Surveillance in South Africa In response to rising clinical cases in Gauteng in November 2021, genomic surveillance efforts increased in the province—shortly thereafter identifying six highly mutated clinical samples that would eventually be classified as the omicron variant. These findings were proactively used to further intensify genomic surveillance, conduct epidemiologic analysis, share the genomes of the samples, and disseminate the information globally, successfully alerting the global community to omicron. Photo credit: ©2011, Sokomoto Photography for International AIDS Vaccine Initiative (IAVI) Argentina’s Targeted Testing and Surveillance Over the first few years of the pandemic, Argentina proactively conducted targeted testing and surveillance activities where community transmission was recognized, such as door-to-door epidemiologic investigations. Based on evolving epidemiology, Argentina pivoted in April 2022, implementing an epidemiological surveillance strategy for several acute respiratory infections to monitor their frequency, distribution, severity, and population impact. Photo credit: HM Treasury Uruguay’s Active Approach to Testing and Surveillance The primary strategy for testing and surveillance in Uruguay involves widespread availability of testing, coupled with aggressive contact tracing, targeted testing during outbreaks, and sentinel surveillance. As the pandemic and resource capacity have evolved, Uruguay’s strategies have as well, to emphasize implementation of centralized genomic surveillance for variants and supplementation of testing capacity with antigen testing. Photo credit: dronepicr Executive Summary Full Report Executive Summary What Is in the Strategy Toolbox? Surveillance Requirements For nearly all surveillance activities in this guidebook, testing capabilities are required, meaning requisite testing capacity and resources are essential for the success of In public health terminology, surveillance activities. surveillance is Testing Testing “collection, the ongoing, systematic analysis, and capacity resources interpretation of health-related Essential data essential to planning, factors implementation, and evaluation $ al of public health practice. (definition from United States Centers for ” Disease Control and Prevention [USCDC]) Successful SARS-CoV-2 Surveillance Surveillance Methods Additional The guidebook describes how the two methods of collecting essential surveillance data—passive and active—can be leveraged to factors proactively inform public health measures for the control of SARS-CoV-2. Both have a role to play in a comprehensive, national population-level testing strategy. Executive Summary Full Report Executive Summary Passive Surveillance Active Surveillance Passive surveillance is opportunistic and reactive, often Active surveillance is more purpose-built. It involves actively using existing activities or resources to collect data on SARS- reaching out to capture new data for a specific purpose and to CoV-2. Passive surveillance may not require substantial new support action towards achieving specific goals. Active surveil- investment, but the data captured may underrepresent lance may require additional resources, specimen collection, groups in the population because a passive approach does and planning, but the data collected will better represent the not intentionally set out to collect a representative sample or whole population or a specific group that may need attention. engage hard-to-reach groups. For SARS-CoV-2, examples of For SARS-CoV-2, examples of active surveillance include: passive surveillance include: Syndromic surveillance Contact tracing and testing Hospital-based surveillance Serial testing in workplaces, schools, health facilities, or congregate settings Mortality-based surveillance Representative population and sentinel surveys Serosurveillance Targeted testing and surveillance Wastewater-based surveillance Prospective epidemiologic studies Genomic surveillance Executive Summary Full Report Executive Summary What Is Required to Implement National Testing and Surveillance Strategies? The process of implementing national testing and surveillance strategies occurs in four key phases—and these should be repeated as neces- 1 sary in response to changing context, resources, and epidemiology. This approach of thinking about Assess existing your strategy as a cycle—rather than as a static, surveillance approaches one-time process—emphasizes the need to stay and available resources nimble and responsive to the ever-changing land- Consider: What do you currently know? What don’t you know? scape of the pandemic. ? 4 2 ? Evaluate the strategy, adapt it, and renew the cycle Consider priorities and Consider: What worked in the develop preliminary strategy first implementation cycle? Can Consider: Will your program focus you ensure the data are used and on a broad population or specific communicated more effectively? groups, or both? 3 Engage stakeholders to refine, optimize, and implement the strategy Consider: Who will lead the program? Is lab capacity adequate? Executive Summary Full Report Executive Summary Why Do Effective National Testing Strategies Matter? Large disparities exist among countries in their manage- Countries that have been more successful tend to: ment of SARS-CoV-2. Few countries have performed well across all waves and stages of the pandemic. This is due, Have a multifaceted surveillance in part, to the effectiveness of their testing and surveil- approach to understand transmission— lance systems. not relying on a single approach to surveillance Well-designed national strategies for SARS-CoV-2 testing and surveillance make a difference in overall pandemic control. As the pandemic continues and is exacerbated Have the ability to proactively use by increasingly transmissible variants of concern, a surveillance to inform effective control national testing and surveillance strategy—using the and prevention responses cyclical process described in this guidebook—is vital to ensure efficient delivery of scarce resources, protect population health, and mitigate the social and economic Have effective systems to quickly test, trace, impacts of COVID-19. and isolate contacts of identified cases Be committed to carrying out targeted community testing where necessary Have capacity to perform sequencing to $ identify, monitor, and respond to emerging variants of interest and concern Executive Summary Full Report Contents Acknowledgments............................................................................. xiv 1: Situation Overview 1 Testing and Surveillance Systems Remain Underdeveloped and Underresourced.......................................................................................... 3 Moving From “Pandemic” to “Endemic”.................................................... 3 The Pandemic Has Several Key Drivers .................................................... 4 2: The Value of National Testing and Surveillance Strategies 6 Effective National Testing and Surveillance Strategies Matter............. 6 Why Else Do Countries Need a National Testing and Surveillance Strategy?...................................................................................................... 8 What Is the Public Health Value of a National Testing and Surveillance Strategy? ............................................................................ 10 3: The Strategy Toolbox 15 Passive and Active Surveillance Approaches..........................................15 Passive Approaches to Testing and Surveillance....................................16 Spotlight on Wastewater-Based Surveillance ........................................21 Active Approaches to Testing and Surveillance.....................................22 Spotlight on School-Based Testing and Surveillance ..........................26 The Testing Armamentarium.....................................................................28 Surveillance Case Examples......................................................................30 Toward a Proactive Approach to National Testing 4:  and Surveillance 36 Phase 1 — Assess........................................................................................38 Phase 2 — Develop ....................................................................................43 Phase 3 — Implement ................................................................................ 47 Phase 4 — Evaluate ....................................................................................54 The Process Is Cyclical............................................................................... 57 References.................................................................................................. 59 Figures Figure 1a. Cases Associated with COVID-19 as of December 1, 2022..............1 Figure 1b. Deaths Associated with COVID-19 as of December 1, 2022........... 2 Figure 2. The Impact of the SARS-CoV-2 Pandemic on GDP in LAC.............. 2 Figure 3. Drivers of the COVID-19 Pandemic and How National Testing Strategies Address Them..................................................................................... 5 Figure 4. National Testing and Surveillance Strategies Support Proactive Responses...............................................................................................................8 Figure 5. The Different Purposes of Testing in Public Health........................ 10 Figure 6. National Testing and Surveillance Strategies Support Many Aspects of the Public Health Response............................................................ 11 Figure 7. Global Vaccination Rates as of December 1, 2022........................... 13 Figure 8. Comparison of Passive and Active Surveillance Approaches....... 16 Figure 9. Steps for Wastewater Testing.............................................................20 Figure 10. Active Approaches to Surveillance Reduce Bias...........................22 Figure 11. Three Approaches to School-Based Testing and Surveillance....26 Figure 12. Phases of the National Testing and Surveillance Program Cycle......................................................................................................37 Figure 13. Considerations to Support the Selection of Surveillance Approaches...........................................................................................................40 Figure 14. Key Human Resources to Engage When Implementing Your Strategy.................................................................................................................48 Tables Table 1. Passive Testing and Surveillance Approaches Summary .................17 Table 2. Active Testing and Surveillance Approaches Summary ..................23 Table 3. Breakdown of the Four Types of SARS-CoV-2 Testing .....................29 Table 4. Other Surveillance Metrics to Inform Overall Approach..................39 Boxes Box 1. Definition of Testing and Surveillance Systems...................................... 3 Acknowledgments This work was made possible by grant funding support from the Korea- World Bank Partnership Facility (KWPF), an initiative between the Republic of Korea’s Ministry of Economy and Finance and the World Bank. The authors would like to gratefully acknowledge and thank graphic designer Danielle Willis and translator Antonio Posada. 1 1 Situation Overview Since early 2020, COVID-19, caused by severe acute respiratory Effective Testing syndrome coronavirus 2 (SARS-CoV-2), has taken hold and spread across the world. All countries in Latin America and the Caribbean and Surveillance (LAC) have been affected, with over 78 million diagnosed cases of Systems Remain COVID-19 and over 1.7 million deaths occurring by December 1, 2022 Critical (figures 1a, 1b) (Ritchie et al. 2022). Figure 1a. Cases Associated with COVID-19 as of December 1, 2022 CASES (PER MILLION) ≥300,000 125,000 to <300,000 15,000 to <125,000 <15,000 No data IBRD 46349 | DECEMBER 2022 Photo credit: Herry Lawford The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 2 Figure 1b. Deaths Associated with COVID-19 as of December 1, 2022 Figure 2. The Impact of the SARS-CoV-2 Pandemic on GDP in LAC SARS-CoV-2 pandemic Economic recovery for some countries in LAC will occur beyond DEATHS (PER MILLION) 2023 ≥ 2,000 1,000 to < 2,000 100 to <1,000 <100 2019 GDP GDP No data IBRD 46350 | DECEMBER 2022 6.7% The emergence of highly transmissible variants of concern—such as delta and omicron—and the evolving path to community immunity may continue to perpetuate the COVID-19 pandemic for years to come. In 2020, gross domestic product (GDP) in the region contracted by 6.7 percent. Although 2021 was a year of economic recovery for many countries in LAC, economic growth slowed somewhat in 2022 and may slow further in 2023; moreover, it is projected that some of the region’s 2020 2021 2022 2023 countries will see rebounds in their GDP to 2019 levels in 2023 or beyond (figure 2) (World Bank 2022; IMF 2022). The continued health, social, and Time economic impacts of COVID-19, and of ongoing world events, threaten to reverse decades of advances in Latin America and the Caribbean and disrupt further progress on remaining health sector challenges. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 3 Testing and Surveillance Systems Remain This lack of action has had substantial consequences. As the omicron variant and its subvariants have become dominant and led to an explo- Underdeveloped and Underresourced sion in infections, limited testing capacity has led to countries in LAC— Testing and surveillance systems (box 1) are cornerstones of the and indeed many others worldwide—to prioritize PCR testing for only COVID-19 pandemic response. They track the evolution of the COVID-19 the highest risk groups, with others either unable to get tested or left to pandemic; identify emerging mutations, variants of interest, and variants search for often expensive antigen tests that are in short supply. This has of concern; support our understanding of the individual- and popula- necessarily limited the ability of governments to respond with precision tion-level impacts of the pandemic; and help guide public health policy. to the levels of transmission seen with the omicron variants and poten- Yet, more than three years after SARS-CoV-2 was first identified, testing tially fueled community transmission due to many individuals’ being and surveillance systems in many countries remain underdeveloped and unaware of their infection status. Indeed, overwhelmed testing and underresourced—sometimes critically. At the onset of the pandemic, surveillance systems have largely failed during the omicron wave and testing was one of the most critical nonpharmaceutical interventions beyond. However, it is not too late for countries to strengthen testing available, supporting contact tracing efforts and early insight into SARS- and surveillance systems to be better prepared for subsequent phases CoV-2 epidemiology. Indeed, without pharmaceutical interventions of the pandemic and future public health threats. (such as vaccines and therapeutics), testing and other nonpharmaceu- tical measures (such as masking, ventilation, and distancing) were the only defenses against SARS-CoV-2, and strong testing and surveillance Moving From “Pandemic” to “Endemic” systems supported effective responses. Although polymerase chain Although the world has safe, effective vaccines for SARS-CoV-2— reaction (PCR) testing capacity was scaled up early in the pandemic, and with many other candidates in development—and there are effective the Pan American Health Organization (PAHO) distributed millions of therapeutics, countries face many challenges as they move through the diagnostic test kits throughout LAC, further bolstering of PCR testing next pandemic phases. Even though endemicity is near certain, the path capacity—and the infrastructure and human resources required to countries will follow to reach it can still be shaped. Underdeveloped and sustain it—has not been a top priority. underresourced testing systems pose a great barrier to control, as do inequities in access and delivery of vaccines. Meanwhile, the potential arrival of variants of concern that may be more transmissible and/or Box 1. Definition of Testing and Surveillance Systems lethal threaten to overrun health systems and perpetuate new waves of disease. The world is tasked with preventing and controlling SARS- The term “testing and surveillance systems” in this guidebook CoV-2 for years to come. describes the collective approaches employed for the purposive, ongoing, and systematic collection, analysis, and interpretation of Comprehensive national public health strategies are required to health data for the purposes of planning, implementing, and evalu- protect vulnerable populations, keep economies open, and avoid the ating public health interventions and programs (German et al. 2001). consequences of future waves. Population-level testing and surveillance must be a key component of those strategies. Such testing and surveillance The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 4 provide epidemiological information on how COVID-19 is affecting countries achieve high vaccination coverage, maintaining national testing communities and can be used proactively to inform decisions on public and surveillance strategies will be essential to detect and understand health measures. This guidebook outlines how to design, implement, and breakthrough infections, understand correlates of protection, identify monitor population-level testing and surveillance strategies to support early indicators of resurgence, and detect new variants. Country by evidence-based decision-making for ongoing prevention and control of country, the approach to testing and surveillance will shift with SARS- SARS-CoV-2 and future public health threats. CoV-2 epidemiology. Testing and surveillance approaches support our understanding of current transmission dynamics, help monitor for The Pandemic Has Several Key Drivers resurgence during periods of low transmission, and allow evidence- There are several characteristics of SARS-CoV-2 that help drive the based responses. pandemic in Latin America and the Caribbean and globally (figure 3). The aim of this guidebook is to provide ministries of health, policy makers, People infected with SARS-CoV-2 exhibit a wide range of responses. An and implementers with the rationale for increased investment in testing infected person may have no or mild symptoms, or they may become and surveillance systems—for SARS-CoV-2 and beyond—and for the extremely ill and die from the disease. Gold standard diagnosis of SARS- value national testing and surveillance strategies offer. We first provide CoV-2—polymerase chain reaction (PCR) testing—requires adequate this rationale in Section 2, and then delve into the key testing and surveil- laboratory infrastructure and is expensive and resource intensive, and lance approaches that should be considered when developing national the necessary materials and reagents have sometimes been difficult to strategies in Section 3. From a public health perspective, in Section 4 we obtain due to fractured global supply chains. These challenges make propose an iterative framework that countries can leverage to design, diagnosis of SARS-CoV-2 difficult. SARS-CoV-2 is highly transmissible, implement, and evaluate their testing and surveillance strategies. making it difficult to control. This is compounded both by asymptomatic and presymptomatic transmission and by heterogeneity in transmission among those infected—where some individuals will never transmit and others will transmit to dozens of people. Over the evolution of SARS-CoV-2, variants of concern such as delta and omicron have increased the efficiency of transmission—a pattern that may continue Inequities in income, living conditions, flexibility but is impossible to predict. Finally, SARS-CoV-2 is difficult to monitor of employment, and access to health services effectively and equitably. Inequities in income, living conditions, flexibility of employment, and access to health services (including SARS-CoV-2 (including SARS-CoV-2 testing) make it hard to testing) make it hard to reach certain groups for testing and hard for reach certain groups for testing and hard for some groups to follow public health measures. some groups to follow public health measures. To address the multiple drivers of the pandemic, multifaceted approaches to case detection and population-level surveillance are required. Even as The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 5 Figure 3. Drivers of the COVID-19 Pandemic and How National Testing Strategies Address Them Drivers of the Pandemic Benefits of National Testing Strategy COVID-19 is: When an Difficult to detect Effective, Supports expanded detection Response to infection varies from National People with either asymptomatic or no symptoms to extreme illness Testing and symptomatic infection or previous and death Surveillance infection can be identified Strategy Is Implemented Supports surveillance activities Difficult to diagnose Comprehensive strategies contribute Diagnosis is resource intensive, requiring people to have capacity, $ greatly to all levels of surveillance, improving forecasting and detection of opportunity, and motivation to be variants of concern tested Supports prevention and care activities Readily transmissible Identification of transmission hot spots Even with adequate vaccination, and changing epidemiology helps SARS-CoV-2 transmissibility is allocate resources and timely response high, regardless of symptoms to break transmission chains Difficult to equitably and Supports equity and population- completely measure based surveillance Case detection is poor for some Representative samples of the groups (many cases are not population are covered, unveiling diagnosed), leading to inequitable inequities and permitting targeted health burden responses The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 6 2 The Value of National Testing and To prevent and control SARS-CoV-2, countries need comprehensive Surveillance Strategies strategic plans. Important elements include social and financial support to help people manage through the pandemic; strategies to The Critical Role Testing and increase and maintain vaccination coverage; nonpharmaceutical measures such as distancing, masking, ventilation, contact tracing, Surveillance Play in Public Health and testing; and population-level surveillance activities. Emergency Response Testing and population-level surveillance activities are an underappreci- ated but vital component of national strategic plans. As part of a national testing strategy, testing and surveillance activities bring indispensable value to a country’s public health response, providing information that can support proactive rather than reactive measures. Testing and surveillance activities continually inform where to direct scarce health resources (including therapeutics); identify areas of transmission; monitor population health indicators (for example, for vaccines); and are essential for tracking emerging mutations, variants of interest, and variants of concern. We describe each of these values in more detail below. But first, we will look further into the “business case” for building a comprehensive approach to testing and surveillance. Effective National Testing and Surveillance Strategies Matter Large disparities exist among countries in their management and response to SARS-CoV-2. Few (if any) countries have performed well across all waves and stages of the pandemic. This is due, in part, to Photo credit: World Bank / Sarah Farhat how effective testing and surveillance systems are and how effec- tively they can proactively apply testing and surveillance data to their pandemic response. Well-designed national strategies for SARS-CoV-2 testing and surveillance make a difference in overall pandemic response and The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 7 control. Countries that have been more successful—as measured compared to many other countries. Throughout the pandemic, including by COVID-19 deaths per million population—tend to have a strong before the arrival of vaccines, testing and surveillance activities have commitment to testing, as well as: been used to inform the intensity of public health restrictions. Early on, genomic surveillance was leveraged to inform track-and-trace efforts A multifaceted surveillance approach to understand and the timing and intensity of restrictions (Geoghegan et al. 2021), and transmission New Zealand submitted sequences for a large fraction of its COVID-19 positive samples to GISAID. However, this effort has waned in 2022, The ability to proactively use surveillance to inform and now only 1.4 percent of all COVID-19 positive samples have been effective control and prevention responses sequenced and submitted to GISAID as of December 2022.1 For the Republic of Korea, experience with middle east respiratory Effective systems to quickly test, trace, and isolate syndrome (MERS) proved useful in developing an effective response contacts of identified cases to SARS-CoV-2. Taking lessons from the past, the republic has made transparency and communication paramount since the start of the pandemic, building public confidence in the response to SARS-CoV-2 Commitment to carrying out targeted community and providing evidence to support mitigation strategies (Oh et al. 2020). testing where necessary Though the scale of transparency with genomic surveillance is not ideal— only around 0.4 percent of all positive sample have had their sequence Capacity to perform sequencing to identify, monitor, and shared with GISAID as of December 20222—vaccination rates in the $ respond to emerging variants of interest and concern country remain high. One of the most important aspects of the country’s success, particularly early on, was a commitment to developing testing New Zealand and the Republic of Korea embraced many of the above capacity; aggressive contact tracing and testing, largely relying on digital principles and mounted effective responses to SARS-CoV-2 through technologies and analytics; and targeted testing and surveillance, which integration of testing and surveillance activities as core components were leveraged from the onset of the pandemic and before the arrival of in public health strategies during the first few years of the pandemic. vaccines. These approaches made the Republic of Korea one of the global leaders in testing by the end of 2021—testing over 70 individuals for every For New Zealand, a combination of clear, consistent messaging from SARS-CoV-2 infection identified. However, throughout 2022—and like political leaders, strong surveillance, very high vaccine uptake, and many countries worldwide—testing fell sharply, and by June 2022, only evidence-based implementation of public health interventions were around five tests were performed per infection. critical to its success in navigating the pandemic in 2020 and 2021—and achieving one of the lowest COVID-19 death rates in the world during 1 GISAID. COVID-19 Sequence Submission Tracking. Available: https://www. this time. Though cases and deaths have increased with omicron and its gisaid.org/. subvariants in 2022, New Zealand’s death rate continues to remain low 2 Ibid. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 8 Why Else Do Countries Need a National Testing Figure 4. National Testing and Surveillance Strategies and Surveillance Strategy? Support Proactive Responses • To get ahead of the next wave of infections. Countries have strug- gled to catch up to and flatten the surges in SARS-CoV-2 infections. National testing and surveillance strategies can help countries To catch up to the next To get ahead of the next forecast what is coming and plan their response (figure 4). wave of infections, wave of infection, countries have been reactive countries should consider • Symptom-based testing alone is insufficient. Although we have and implemented extreme employing surveillance, using nearly two years of experience with the SARS-CoV-2 virus, most of public health measures. a wider testing strategy (who the world is flying blind with respect to variants of concern during the These reactive measures are is tested, where, and how pandemic, and many countries still lack epidemiologic data on the not sustainable long-term often), to inform public health dynamics of the virus—data that are useful for prioritizing vaccina- and lead to substantial strategies, including tion and public health measures. adverse economic and social immunization programs. consequences for the The backbone testing approaches for SARS-CoV-2 prevention and populations subjected to control are important, but by themselves they are not enough to such measures. provide adequate information for public health strategies. These backbone approaches include: » Testing clinically presenting cases (that is, people with symptoms) and people who self-present to assessment centers. Countries with more comprehensive testing systems have gener- ally managed the pandemic better. » Tracing and testing contacts. To break chains of transmission, Reactive Proactive engage people with the health system, and understand measures measures transmission dynamics, tracing and testing of contacts is a critical nonpharmaceutical intervention available to countries. Infection wave • SARS-CoV-2 variants continue to emerge. Variants that are more transmissible and/or virulent than the wild-type SARS-CoV-2 strain consistently emerge—and three have originated in LAC.3 As we 3  WHO (World Health Organization). Tracking SARS-CoV-2 Variants. Available: https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 9 have seen with the delta and omicron variants, these variants can take hold quickly, overwhelming underprepared health systems. As SARS-CoV-2 is in animal reservoirs, zoonotic transmission (transmis- sion from animals to humans) is possible, and variants may continue to emerge despite widespread population immunity. • Inequities will continue to persist with a passive approach to SARS-CoV-2. A national testing and surveillance strategy considers the factors that help perpetuate community transmission: » Severity. Severe clinical disease occurs in a minority of all SARS- CoV-2 infections. People who are more likely to have milder disease are also those most likely to have more contacts (and may never be diagnosed). » Transmissibility. Some people can infect many others. Spread occurs more in crowded and confined spaces, particularly those with poor ventilation. » Identification. People with no symptoms (asymptomatic) or few symptoms (pauci-symptomatic) are unlikely to self-present to assessment centers and receive a diagnosis. The potential for appreciable transmission during the asymptomatic phase of infection means cases and their contacts may never be identified. » Age. Younger people are more likely to present with no or minimal symptoms. » Access. Vulnerable populations often have less access to health care and find it harder to follow public health guidance. These ineq- uities place them at higher risk of infection and severe outcomes such as death. Photo credit: Tim Dennell The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 10 What Is the Public Health Value of a National Figure 5. The Different Purposes of Testing in Public Health Testing and Surveillance Strategy? There are numerous benefits to having a national testing and Diagnostic surveillance strategy. Such strategies may leverage testing for several Testing is performed on individuals with purposes: diagnostic testing, screening testing, and/or testing for public a prior suspicion of infection to confirm a health surveillance (figure 5).4 The scale to which each of these testing diagnosis. This includes people presenting approaches are implemented is influenced by the available resources with symptoms consistent with COVID-19 or those with known or suspected recent (financial, human, and infrastructure) and current epidemiology. exposure to someone with SARS-CoV-2. National testing and surveillance strategies are a key link in the chain of public health responses (figure 6) and support several aims, as outlined below. Screening To Inform Resource Allocation Testing is performed on individuals without symptoms consistent with COVID-19 and Countries should design a testing and surveillance strategy to provide without known or suspected recent exposure. as much information as possible on which populations are being Testing serves to identify people with unknown affected by COVID-19, where they are, and how and when transmis- infection, particularly in settings with elevated sion is happening. Such information is critical to proactively inform risk of transmission or among populations at the use of pharmaceutical and nonpharmaceutical interventions, to elevated risk of severe outcomes. direct population-level supports, or to direct use of scarce sequencing resources, among other actions. Surveillance To Understand Transmission Dynamics Among Priority Testing data is aggregated or collected in a Populations nonidentifying manner (that is, data are not Effective national testing and surveillance strategies are an invaluable linked to an individual) for the purposes of public health surveillance. Surveillance data nonpharmaceutical intervention that can contribute to reducing trans- for SARS-CoV-2 may be collected for purposes mission. A national strategy allows a country to implement proactive of monitoring transmission, estimating or preventive strategies to mitigate transmission where they might have monitoring the incidence or prevalence the most impact. of disease or outcomes, or estimating or monitoring population immunity. 4 USCDC (United States Centers for Disease Control and Prevention). Testing Strategies for SARS-CoV-2. Available: https://www.cdc.gov/coronavi- rus/2019-ncov/lab/resources/sars-cov2-testing-strategies.html. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 11 Figure 6. National Testing and Surveillance Strategies Minimizing transmission is essential for economic recovery. Robust Support Many Aspects of the Public Health Response testing systems, along with vaccination, are key inputs in broader public health responses that keep schools and businesses open. The omicron variant and its subvariants have demonstrated that even among highly When all links in the response chain are strong: vaccinated populations, transmission can readily occur. In populations A coordinated response to the emergency can be developed and robustly implemented, with ongoing monitoring, evaluation, and without very high vaccination coverage, transmission can be expected forecasting to proactively update strategies to evolving circumstances. to continue for years. Transparent, clear, and consistent messaging can be delivered to Beyond contacts of identified cases, areas and populations that may be promote trust in recommendations. Inequities can be identified and addressed, and required population-level supports can be provided to prioritized by focused testing strategies can include: encourage adherence with public health recommendations. • Vulnerable populations, such as the elderly or those in congregate settings. • Geographic transmission hotspots, which may not be detected by clinical testing until there is substantial community spread. Policy-makers, Situation Infrastructure, Population monitoring, networks, economic and • Schools, which may form a high-risk environment for close contact experts, other evaluation, health and Communication social and can lead to transmission occurring outside the school. stakeholders and human supports forecasting resources • High-risk employment sectors, such as health care. Undetected spread in hospitals and health facilities can impede functionality and lead to transmission to vulnerable populations. High-risk sectors include other jobs that put people into repeated contact with co-workers and the public: people in these jobs may be exposed and never know it, which can lead to closing of workplaces. When weaknesses exist in the response chain: • Key economic sectors, which will vary specifically by country. The overall effectiveness of the emergency response is hindered. For Proactive use of testing and surveillance data can support keeping example, weaknesses in monitoring, evaluation, and forecasting impair how quickly new variants may be identified or other changes in jobs and economies protected. epidemiology are detected, leading to reactive responses. This can also mask inequities, leading to their exacerbation. Weaknesses at any part of the response chain are felt throughout, limiting the impact of the overall response. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 12 To Support Vaccine Surveillance Strong testing and information systems are essential for vaccine surveillance (for example, coverage, effectiveness, safety). There is extensive synergy between systems required for vaccine monitoring and roll-out and those required for testing. With over two years of experience with SARS-CoV-2 vaccines and the emergence of numerous variants, understanding the correlation between vaccination and protection against both infection and severe outcomes (for example, hospitalization and death) is essential to guide vaccination plans and estimate population protection. Testing is a critical tool to be used alongside vaccines, as it helps a country track population immunity (the current degree of vulnerability to SARS-CoV-2), understand the local effectiveness of vaccines, and monitor vaccine coverage. • Vaccine-acquired immunity and infection-acquired immunity must be monitored via population testing. » This type of surveillance allows targeted revaccination among populations with waning immunity (such as immunocompro- mised populations). » Monitoring population immunity also indicates the duration and extent of vaccine protection, particularly in the context of emerging variants. Photo credit: Erick Kaglan / World Bank • The real-world effectiveness of SARS-CoV-2 vaccines varies across populations and variants of concern. » This is important for understanding where additional support and public health measures may be required. » Testing will continue to play a role in detecting transmission, even in vaccinated populations. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 13 • Vaccine inequity is a major global problem (figure 7), and vaccine Figure 7. Global Vaccination Rates as of December 1, 2022 hesitancy puts even areas with high levels of vaccination at risk. » Transmission will continue to occur in populations that do not have high vaccination coverage and, with the emergence of variants, may continue to occur at high levels among vaccinated populations. » Continued testing and monitoring of both vaccinated and unvaccinated populations remains imperative. To Support Genomic Surveillance A key integration into robust testing systems is that of genomic surveillance. In its simplest form, genomic surveillance supports the rapid identification of emerging mutations that may lead to SARS-CoV-2 VACCINATIONS (PER 100) ≥200 variants of interest and variants of concern. As SARS-CoV-2 replicates, 100 to <200 <100 new mutations occur approximately once every two weeks (Robishaw No data et al. 2021). PAHO has created the COVID-19 Genomic Surveillance IBRD 46351 | DECEMBER 2022 Regional Network to help support collection, analysis, and action on emerging variants.5 The World Health Organization (WHO) recommends that 5 percent of » Robust genomic surveillance systems in Botswana and South all SARS-CoV-2 specimens be sent for genome sequencing to support Africa (see the case example), contributed to the rapid iden- genomic surveillance efforts (WHO 2021). Although this is a high bar, tification and dissemination of the omicron variant after cases there are numerous benefits to incorporating genomic surveillance into surged in Gauteng province, South Africa. Previously, systems testing strategies, even as countries work to expand capacity to achieve in the UK were leveraged to quickly identify the alpha variant WHO levels. after an expanding cluster of COVID-19 cases was recognized in southeastern England. These systems alerted the world to • SARS-CoV-2 variants will continue to emerge—including from variants of concern and permitted extensive, rapid evaluation of zoonotic reservoirs—and timely identification can support global their characteristics. efforts to understand transmissibility, virulence, and immune- » A library of global SARS-CoV-2 genomes further supports devel- evasion potential. opment of new diagnostics, therapeutics, and vaccines that may overcome loss of efficacy associated with new variants.6 5  PAHO (Pan American Health Organization). COVID-19 Genomic Surveillance Regional Network. https://www.paho.org/en/topics/influenza/covid-19-genom- 6  GISAID. COVID-19 Sequence Submission Tracking. Available: https://www. ic-surveillance-regional-network (accessed April 25, 2021). gisaid.org/. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 14 • Genomic surveillance supports molecular epidemiological inves- tigations aimed at understanding transmission dynamics in local outbreaks. » As more of the world becomes vaccinated against SARS-CoV-2, genomic surveillance improves our understanding of transmission between vaccinated and/or unvaccinated individuals, immune evasion potential (mutations that may allow the virus to evade detection by antibodies), and the risk of overdispersion in trans- mission (that is, superspreader risk). • Infrastructure and networks for genomic surveillance can support the development of mitigation measures and be leveraged for other pathogens. » Early identification of a variant of interest or concern can support rapid response and mitigation measures to quell its spread while more information is gathered, giving other regions and countries time to prepare. » Beyond SARS-CoV-2, genomic surveillance infrastructure can be readily leveraged for many other purposes, such as monitoring antimicrobial resistance or epidemiological investigation of other pathogens, such as tuberculosis. Photo credit: Nenad Stojkovic The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 15 3 The Strategy Toolbox The Advantages and Disadvantages of Different Testing and Surveillance Passive and Active Surveillance Approaches and Their Applications Approaches There are two basic approaches to SARS-CoV-2 testing and surveil- lance—passive approaches and active approaches. Both have a role to play in a comprehensive, national strategy that proactively informs public health response (figure 8). Passive approaches are oppor- tunistic and reactive. Passive approaches often make use of existing activities, events, resources, or specimens typically not collected for the primary purpose of surveil- lance, to collect data on SARS-CoV-2. Testing blood samples available from donations or routine blood tests is an example of passive surveillance. So too is using testing data emerging from symptomatic people who self- present to testing centers. The main advantage of passive approaches is that they typically do not require substantial new or ongoing investment and make use of existing systems, samples, and/ or data. The primary disadvantage is that passive approaches may not Photo credit: Tim Dennell The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 16 Figure 8. Comparison of Passive and Active Surveillance provide a full, accurate picture of the whole population; data captured Approaches from passive approaches can underrepresent groups that are less likely, for example, to self-present at testing centers or to donate blood. As a • Passive strategies are generally opportunistic and result, data from passive approaches may be subject to biases. A key Passive strategies reactive. example is selection bias, in which the data we collect may lead to erro- • These approaches make use of resources and/ neous conclusions if we try to generalize to a population level, because or events that generally would occur without any the people included in the strategy are not representative. additional intervention. Active approaches are more purpose built and are undertaken with • Where testing is performed on individuals, the onus the primary goal of collecting data for surveillance. This category tradi- to present for testing is on the person. tionally includes approaches that reach out to capture new data for a • Data collected are more likely to be subject to biases specific purpose or to ensure a representative sample of the popula- than in active approaches. tion. Aggressively tracing and testing contacts of people with COVID-19, • Syndromic surveillance and wastewater-based regular testing of essential workers, and targeted community testing are surveillance are examples of passive approaches. examples of active surveillance approaches. The main advantage of active approaches is that they can provide data above and beyond what passive approaches can produce and, when • Active strategies attempt to carefully gather applied appropriately, are less subject to biases inherent to many passive Active strategies information. approaches. The key disadvantage is that active approaches are gener- • Active approaches should be based on clear goals ally more resource intensive. Such approaches require careful planning, and a sustainable implementation plan. monitoring, and evaluation, with attendant investment of both financial • They require additional resources to collect data or and human resources. For example, effective implementation of tracing samples necessary for testing. and testing of COVID-19 contacts requires dedicated infrastructure (for example, computing capabilities, secure data repositories, office space), • Where testing is performed on individuals, the health care system generally works to collect samples. routine monitoring and evaluation activities, and the staff and money necessary to achieve high coverage of reported cases and their contacts. • Data collected through active approaches are less likely to be subject to biases than in passive approaches, as details such as participant selection Passive Approaches to Testing and Surveillance are more controlled. This guidebook covers six approaches to passive, population-level surveillance of SARS-CoV-2: syndromic surveillance, hospital-based • Contact tracing and testing and serial workplace surveillance, mortality-based surveillance, serosurveillance, testing are examples of active approaches. genomic surveillance, and wastewater-based surveillance (table 1). The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 17 Table 1. Passive Testing and Surveillance Approaches Summary Passive approach Primary aim What it measures Main advantages Main disadvantages Future applications To monitor self- Current COVID-19 in Laboratory Requires engagement Already in place reported symptoms the community confirmation not with the specific in many areas for in the community; necessary; can cover a surveillance activity— influenza-like illness; Syndromic notifications for large proportion of the may be subject can be readily adapted specific illnesses population, including to selection bias; to validated algorithms surveillance at sentinel sites, those that don’t potentially not highly for other illnesses purchasing or internet typically seek care; specific search trends, and potential early-warning others system To systematically Current and previous Can leverage existing Population presenting Hospital resource (based on indication SARS-CoV-2 infection staff and resources to hospitals is allocation; efficacy of Hospital-based or at random) test in the community for in-hospital testing; selected and unlikely nosocomial (in hospital) surveillance individuals presenting good coverage of to represent the protections; morbidity to hospital people with severe community (selection and mortality outcomes disease bias) of other illnesses To monitor trends in COVID-19 in the Can capture excess Typically slow and lags Mortality (all-cause and all-cause mortality community and net mortality (diagnosed case data; represents cause-specific) trends Mortality-based and COVID-19-specific harms of pandemic and undiagnosed historic burden and not in various strata; long- surveillance mortality COVID-19); tracks most current situation term study of health patient-important impacts outcome To monitor trends in Previous SARS- Specimens should be Populations Application for other population immunity CoV-2 infection and readily available; may contributing pathogens (for immunization in the be used to distinguish specimens unlikely example, hepatitis, Serosurveillance community vaccine-acquired vs. to be representative HPV); systems widely disease-acquired of general population applicable beyond immunity (selection bias) serology To monitor community- Current SARS-CoV-2 Leverages existing Requires careful Directly translatable to Wastewater- or setting-specific infection in the infrastructure; precautions and analysis; other pathogens (such trends in active community representative of targeted responses as influenza, polio) and based infection communities or require a sufficiently to drugs and toxins in surveillance settings; potential small population to be the community early-warning system sampled To track currently Incidence and Provides a view into High barriers to entry Broadly applicable to known variants and prevalence of SARS- circulating variants including sequencing other pathogens—such Genomic identify new ones CoV-2 variants in the community capacity, sampling as tuberculosis—that and newly emerging methods among acute acquire mutations Surveillance mutations infections, safe transport of specimens and timely reporting The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 18 Syndromic Surveillance infection, increasing the breadth of information that can be collected. Leveraging syndromic surveillance systems for SARS-CoV-2 allows Like syndromic surveillance and other passive approaches, hospital- programs to passively follow trends of self-reported symptoms in the based surveillance is subject to selection bias, as those presenting or community, trends in purchasing or internet searches, or trends in admitted to the hospital are likely to be different from the population specific medical visits at sentinel sites. Such systems may flag potential in the community. Well-designed hospital surveillance systems offer surges in SARS-CoV-2 before clinical presentation and confirmation value beyond simply tracking admissions and positive tests: they can could do so, constituting an early-warning system. Many countries in Latin give a view of the efficacy of the hospital’s infection prevention and America and the Caribbean already have strong syndromic surveillance control measures, help with resource allocation, and provide insight systems for influenza-like illnesses, which could be adapted and into characteristics associated with severe outcomes. leveraged for SARS-CoV-2. These systems offer a particular advantage as they can cover a large proportion of the community, including many Mortality-Based Surveillance people who may not typically seek care. However, they necessarily In health systems with high coverage and quality of medical death certi- exclude people who do not engage with the particular avenue of data fication, mortality-based surveillance is a useful tool to track the most collection (for example, visits to primary care, internet use), which may important outcome of COVID-19 and the net harms of the pandemic lead to selection bias. Despite this, syndromic surveillance systems may in terms of excess deaths. Mortality-based surveillance data supports support early identification of surges, and systems and infrastructure monitoring of trends in COVID-19-specific mortality and all-cause can be readily adapted to other illnesses for use in the future (Elliot et mortality. Such data can be compared with historic mortality data to al. 2020; Lapointe-Shaw et al. 2020). understand excess harms of the pandemic in terms of mortality, which may be caused by delays in health care or lower quality care due to health Hospital-Based Surveillance system stresses. The success and utility of mortality-based surveillance Many hospital programs have systems in place to track reasons for is dependent on the strength of death registration systems. These hospital admission and provide testing for a variety of pathogens. systems need clear coding for cause of death classifications, accuracy These systems can be leveraged to track the number of admissions for and timeliness in cause-of-death reporting, and linkages from reporting COVID-19 and the positive test rate of people presenting to hospitals. facilities to a central registry. Key limitations include that mortality data Testing could be performed among people being admitted for specific reflect the historic burden of disease, rather than the current burden (as indications (for example, with an immunocompromising condition, COVID-19 deaths lag cases by several weeks and medical death certi- or for antenatal examinations), among a random sample of people, fication may also delay reporting of cause of death), and the reporting or among everyone being admitted. A major benefit is that hospital of deaths occurring outside the health system (such as at home), which staff and resources can be readily used to perform such testing, and poses serious challenges. In systems with strong death registration existing information systems should be able to track reasons for systems, these data are informative for future pandemic waves, support hospital admission. Testing can be done for both current and previous identification of the populations most vulnerable to COVID-19, and The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 19 permit evaluation of long-term trends in health impacts of COVID-19 in Genomic Surveillance the community (such as excess mortality). SARS-CoV-2, like other RNA viruses, is always mutating. In some instances, these mutations may lead to different viral properties that Serosurveillance impact characteristics like transmissibility, virulence, and the ability to Passive approaches to serosurveillance can leverage residual blood evade immunity. Genomic surveillance is a tool that can be leveraged to from donations or routine blood tests to test for specific antibodies to track currently known SARS-CoV-2 variants and identify new mutations. SARS-CoV-2. This method of ascertaining population-level immunity to Such surveillance has immense value at both national and international SARS-CoV-2 is an invaluable tool to understand population protection, levels. In national contexts, identification of case clusters sharing the need for nonpharmaceutical interventions, and necessity of additional same mutation may allow for early response, constraining the variant’s vaccinations. Importantly, in settings where vaccination has largely used potential to spread. In international contexts, open sharing of genomic the currently available mRNA or viral vector vaccines, serosurveillance data supports rapid characterization of emerging mutations, to help can allow programs to understand the prevalence of infection-acquired understand their potential significance. More broadly, robust genomic versus vaccine-acquired immunity (in these populations, seropositivity surveillance data can help identify regions of the SARS-CoV-2 genome for anti-N antibodies suggests infection-acquired immunity [Duarte et that are more likely to change and regions more likely to be conserved, al. 2022]). Selection bias is again a limitation of passive serosurveillance, supporting development of therapeutic options (such as treatments, however, as people donating blood or having blood taken for testing vaccines) that remain effective against future variants. Although it is may not be representative of the larger community. Nevertheless, this challenging to initially implement and develop a genomic surveillance remains a useful approach to augment data on vaccinations, waning network, the potential benefits are immense (Robishaw et al. 2021). immunity, and other infectious pathogens beyond SARS-CoV-2. See the case example from South Africa for how genomic surveillance played an integral role in the early identification and global notification Wastewater-Based Surveillance of the omicron variant. In areas with sewered sanitation systems, routine sampling of waste- water from these systems can be used to detect presence of SARS- CoV-2. People infected with SARS-CoV-2 expel the virus in their feces, making the virus readily measurable in wastewater systems. Because SARS-CoV-2 can be detected in feces before symptoms present, wastewater-based surveillance can be used as an early-warning system, detecting surges before people in the community know they are infected. See the “Spotlight on Wastewater-Based Surveillance” and the case example from Rotterdam for further information (Kaiser 2020). The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance Spotlight on Wastewater-Based Surveillance 20 An emerging passive surveillance approach for COVID-19 Figure 9. Steps for Wastewater Testing Aim: Wastewater-based surveillance offers compar- atively low-cost, population-wide surveillance that does not rely on individuals accessing health care or the availability of clinical testing. 1 2 People become SARS-CoV-2 in infected with stool gets flushed SARS-CoV-2 down the toilet Approach: Test wastewater for SARS-CoV-2 using the same assay methods as clinical testing but 3 Virus particles 4 adapted for wastewater samples. Sample travel through the Sewage sample sewerage system is taken along wastewater at wastewater facilities prior the sewerage to treatment, or further upstream in the shed or at the treatment facility wasteshed, or at specific congregate settings 5 (figure 9). Samples are transported and stored at the laboratory 6 Viral and other measures are taken at the laboratory, after filtration, concentration, and RNA isolation 7 Public health action is informed by sharing data and reports Outcome: A single wastewater test can provide an esti- Openly and transparently share mate of COVID-19 prevalence for an entire to engage the public in Interpret results alongside other Advance wastewater science and surveillance data our understanding of COVID-19 community. prevention and control measures Who Who Who Public, policy actors, and journalists Local, regional, national, and Researchers, students, and international public health along informed public with environment and wastewater collaborators The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance Spotlight on Wastewater-Based Surveillance 21 An emerging passive surveillance approach for COVID-19 Potential utility: Some future uses: Four uses of wastewater-based surveillance have • Later-stage surveillance. Wastewater testing been described. can be used to monitor for SARS-CoV-2 outbreaks, surges, and re-emergence once • Early detection of outbreaks and surges. countries have achieved widespread vaccina- SARS-CoV-2 RNA can be detected in tion coverage. wastewater in advance of laboratory-confirmed clinical cases in a community or population. • Monitoring of other pathogens and health This enables countries to detect SARS-CoV-2 risks. Wastewater testing can be applied to where there is no confirmed transmission and other pathogens of significance and health to identify surges or waves in settings where risks such as antimicrobial drug resistance, as there is established transmission. well as to drug monitoring. • Population-wide surveillance. Wastewater Potential limitations: testing is a population-wide approach that is Wastewater surveillance requires people from complementary to clinical laboratory-based • Viral measurement in wastewater is affected different disciplines to work together. surveillance. Together, these approaches by a range of factors including infection rate, can inform the need for and effectiveness of variation in individuals’ fecal shedding, config- prevention and control measures such as uration of wastewater sewer systems, envi- vaccination. ronmental degradation, and laboratory assay performance. • Population-specific surveillance. Wastewater testing is useful for early detection of SARS- • Evidence regarding the use and benefit of CoV-2 in specific populations and congregate testing is limited but rapidly increasing. settings such as long-term care facilities, • Wastewater testing and interpretation require correctional facilities, shelters, university resi- the expertise of public health agencies, dences, and workplaces. wastewater laboratories, and the respective • Early identification of mutations, variants of regions—and, equally important, ongoing concern, and variants of interest. Wastewater collaboration among them. testing can be used to quickly identify which SARS-CoV-2 variants are circulating in the For more information, see Strengthening Public community and monitor the proportion of Health Surveillance Through Wastewater Testing: variants at the population level. An Essential Investment for the COVID-19 Pandemic and Future Health Threats, another Samples can be taken anywhere there is resource in the LAC COVID-19 Testing Series. wastewater. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 22 Active Approaches to Testing and Surveillance Passive approaches may not capture a representative sample of the population, potentially biasing results. Active approaches to surveillance can reduce bias through purposeful, often more intensive, testing and surveillance (figure 10). This guidebook covers five approaches to active, population-level surveillance of SARS-CoV-2: contact tracing and testing; serial workplace-, school-, health facility-, and congregate setting-based testing; representative population or sentinel surveys; targeted testing and surveillance; and prospective epidemiologic studies (table 2). Figure 10. Active Approaches to Surveillance Reduce Bias The major advantage to active testing and surveillance is that they can yield data above and beyond what may be gathered by passive approaches. This permits proactive, data-driven tailoring of responses to the pandemic Photo credit: Henitsoa Rafalia / World Bank by giving a more accurate picture that may overcome sampling biases from passive surveillance. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 23 Table 2. Active Testing and Surveillance Approaches Summary Active approach Primary aim What it measures Main advantages Main disadvantages Future applications To identify contacts Current SARS-CoV-2 Identify persons Can be time consuming Readily transferable Contact and provide testing to infection and attack unknowingly at high and may require to outbreaks arising inform quarantine and rates (risk of secondary risk of exposure, unsustainable health from other infectious tracing and isolation requirements, transmission) among provide testing and resources when cases pathogens testing as well as other contacts guidance, and reduce are high measures and supports transmission To pre-emptively Current SARS- Permits development Can be laborious Testing platforms Serial testing identify infections in CoV-2 infection and of ongoing snapshots of to organize and can be leveraged for in high-risk settings at high risk for acquisition of infection infection in each setting, implement; can be vaccination and active transmission, permitting in workplaces, schools, allowing for early expensive to the monitoring settings public health responses health facilities, or response to spikes health system and congregate settings inconvenient to participants To collect population- Current and/or previous Can help identify Is generally resource Survey platforms representative SARS-CoV-2 infection in underestimation in intensive and requires can be leveraged for Representative information on current the population case counts, identify clear sampling strategy, other health or social population or previous infections groups that are not logistics of administering applications (such or sentinel at a point in time and to getting tested, detect home-based tests, as census or health track how these change variations in distribution and multiple rounds of surveys) surveys over time in infection, and track testing to be of most use population immunity To collect additional Current and/or previous Can be leveraged in May be resource Surge capacity in information SARS-CoV-2 infection, communities or other intensive depending human resources, labs, on prevalence, and/or prevalence of settings when clinical on the size of the and other resources Targeted transmission risk, and variants in the targeted cases increase, when population targeted necessary for targeted, testing and variants in response to population other changes in and whether repeated intensified testing can surveillance changes in epidemiology epidemiology occur (such testing is required be leveraged for other or unusual signals as identification of a emergencies or uses cluster of mutations), or unusual signals are seen To increase the breadth Varied, specific to study Can be tailored to Requires research Development of a re- and quality of evidence aim and design pressing questions, capacity with search platform at the and answer questions as identified by stake- adequate funding and national level allows Prospective of high public health holders, and provide independence; study self-directed study and epidemiologic importance setting-specific design and deployment, discovery in all areas of studies information including ethical health approval and data sharing, often very time consuming The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 24 Contact Tracing and Testing limiting outbreak growth. Developing an active strategy like this is Contact tracing and testing are a cornerstone of public health responses resource intensive in terms of human resources, logistical support, and to infectious pathogens. Identification of people who may have been cost, requiring high-level commitment from all stakeholders. However, exposed to infected individuals allows appropriate mitigation measures to setting up such testing platforms can reap future benefits as they can be instituted, which may include testing and quarantine of contacts, as well be leveraged for onsite vaccination programs. See the “Spotlight on as provision of necessary social support. Further, this approach provides School-Based Testing” for additional discussion. critical information on epidemiologic parameters, such as serial intervals (time between illness onset and primary and secondary cases) and attack Representative Population or Sentinel Surveys rates (proportion of contacts who become infected), which may change A key limitation of passive approaches to surveillance is that they are with emerging variants. Through contact tracing, individuals at high risk unlikely to be generalizable to the population at large, making their use of exposure—and who may be unaware of the exposure—are notified, limited for some applications. Representative population surveys can and appropriate actions taken. Although contact tracing and testing can overcome this barrier and produce data that are generalizable beyond become resource intensive when unmitigated transmission occurs in the participating sample. Well-designed national prevalence and communities, they can be augmented with digital tools to support their seroprevalence surveys provide a lens into the health of the community. implementation (O’Connell and O’Keeffe 2021) (countries with such infra- When done cross-sectionally, they provide key data on current infections, structure from previous emergencies responded to COVID-19 quickly). as well as on the impact that previous waves of infection have had. If done Countries with strong public health responses to SARS-CoV-2 typically in sufficient size, they can reveal group-specific trends (such as by sex, had robust contact tracing and testing systems—systems readily trans- age, location, occupation). When repeated, they provide further critical ferable to other infectious pathogens, such as middle east respiratory information on how prevalence in the community is changing, supporting syndrome and measles. modeling efforts and development of proactive mitigation strategies. Setting up a platform to conduct such surveys where one does not exist Serial Testing in High-Risk Settings takes time and resources, which may discourage their use in practice. Hotspots of transmission may exist within workplaces, schools, health Success stories of their use highlight the extensive collaboration and facilities, and congregate settings where people tend to gather in close support that are critical for this approach. See the case example from quarters for long periods of time. As SARS-CoV-2 is transmissible even the United Kingdom for how a representative population survey was in the absence of symptoms, symptom-based case detection may result put into action. in high levels of transmission before a primary case is reported. Serial testing in these different settings can pre-emptively identify infections, Targeted Testing and Surveillance limiting the potential for continued transmission. Such testing could also Both passive and active testing and surveillance activities may identify be employed in outbreak situations to support identification of newly populations and/or settings that are experiencing high levels of infected individuals—allowing for their prompt isolation and potentially transmission, unexpected clusters of cases or mutations, or unusual The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 25 changes in epidemiology. Targeted, intensified testing involves focusing mask mandates, widespread testing, and improving ventilation. These testing and surveillance resources following these changes to collect large-scale studies can be initiated by industry, academics, or existing additional information to support proactive responses. Such testing may research capacity at the national level. The latter may take time to take the form of broadening who can be tested (based on age, symptoms, develop but can pay dividends: a sufficiently funded and independent location, occupation, and other factors), actively seeking individuals and research program can help gather answers to questions of national offering SARS-CoV-2 testing, focusing wastewater-based surveillance importance, which may differ from those being investigated globally. See on the population or setting being targeted, or increasing the proportion the case example from Slovakia for how the utility of population-wide of clinical samples or wastewater effluents that are sent for sequencing rapid antigen testing was prospectively evaluated. to identify known or novel mutations. The scale of the targeted response is necessarily limited by available resources, but implementing such activities can provide critical information to inform public health strategies. See the case example in Slovakia, where targeted testing was used in counties with particularly high population prevalence of SARS-CoV-2, and the case example in South Africa, where targeted genomic surveillance helped identify the variant of concern, omicron. Prospective Epidemiologic Studies Despite the best surveillance methods, certain questions simply cannot be answered with currently available data or with other surveillance approaches. In some cases, prospective epidemiologic studies, which seek to answer specific questions, are necessary. Prospective epide- miologic studies can shed light on the potential risks, benefits, costs, and feasibility of different approaches to monitoring and responding to SARS-CoV-2, while also providing valid comparative information on SARS-CoV-2 characteristics such as transmissibility, virulence, and risk for immune evasion. For example, prospective epidemiologic studies may help elucidate attack rates among household contacts of persons infected with SARS-CoV-2, may help estimate real-world vaccine effec- tiveness, and may help discern differences in transmissibility between two or more circulating variants. Such studies may also provide data that can help answer questions on different interventions, such as The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance Spotlight on School-Based Testing and Surveillance 26 An approach to complement symptomatic testing and other preventive interventions in schools Figure 11. Three Approaches to School-Based Testing and Surveillance Rationale and Aim: The COVID-19 pandemic has led to substantial disruptions to in-school learning. Even in September Positive = isolation 2021 (around 18 months into the pandemic), around 86 million children and adolescents in Latin America 1 remained out of classes. School closures have a Serial testing weekly/ Negative = testing continues detrimental effect on children, particularly those from biweekly/ marginalized groups. Studies have shown losses in triweekly reading and numeracy and higher rates of dropout compared to previous years, which may, in part, be due to disruptions to in-school learning.7 Minimizing the risk of SARS-CoV-2 transmission within 2 schools is imperative to keep schools open safely. Wastewater testing Even though symptomatic testing and preventive Sewage sample interventions—including universal masking, is taken along adequate ventilation, and high rates of vaccination— the sewerage are the backbones of strategies to mitigate in-school shed or at the treatment facility transmission, additional testing and surveillance strategies can add another layer of protection and proactively guide mitigation strategies. 3 We describe three potential approaches (figure 11) Test to stay to school-based testing and surveillance that can Contacts complement other preventive interventions. The “test to stay” Positive = isolation approaches are not mutually exclusive and can be Positive case used in combination to add value and increase utility. Non-contacts days Negative = not tested contact Contacts 1, 3, 5, 7 remains identified in school 7  UNICEF. Available: https://www.unicef.org/lac/comu- nicados-prensa/casi-2-de-cada-3-ninos-ninas-y-adoles- centes-siguen-fuera-de-las-aulas-en-america-latina-y-el- caribe. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance triweekly Spotlight on School-Based Testing and Surveillance weekly/ biweekly/ triweekly testing continues 2 Wastewater testing 27 An approach to complement symptomatic testing and other preventive interventions in schools 2 3 Wastewater testing testing continues weekly/ Positive = isolation biweekly/ Positive case triweekly days Negative = 1, 3, 5, 7 contact remains 3 in school Approach 1: Serial testing (PCR or antigen) of Approach 2: Wastewater-based surveillance Approach 3: In response to identifying a case of 2 teachers, students, Wastewater testing and staff to identify asymp- to monitor changes in SARS-CoV-2 RNA at the Positive = isolation SARS-CoV-2, the class, cohort, or close contacts Positive tomatic infections. school. case days 1, 3, 5, 7 Negative = contact are tested (often repeatedly, as on days 1, 3, 5, and 7 after exposure), with those testing negative remains in school Intended outcome. Serial testing on a routine Intended outcome. After establishing a baseline, 3 and being asymptomatic permitted to remain—in basis (weekly, biweekly, triweekly, etc.) supports this approach enables identification of changes a “test to stay” approach. early detection of SARS-CoV-2 infection among Positive = isolation in SARS-CoV-2 in wastewater. Positive asymptomatic people case and may be implemented days Negative = Intended outcome. To continue in-school learning 1, 3, 5, 7 contact Potential utility. Wastewater-based surveillance with self-collection kits for PCR or onsite testingremains while minimizing the number of students, teachers, primarily supports early identification of surges in school with antigen tests. and staff who need to isolate due to exposure. in infection—likely days before symptomat- Potential utility. Early detection of asymp- ic-based detection. This supports proactive Potential utility. The test-to-stay approach tomatic infections prevents opportunities for intervention, such as targeted testing or more complements symptom-based detection, limits transmission and may limit the size and scale of stringent nonpharmaceutical interventions, to the number of school days missed by students, and potential outbreaks. Such programs have been mitigate infection surges. Evidence suggests does not result in more secondary or tertiary cases successfully implemented at several universi- that wastewater-based surveillance correlates compared to approaches entailing quarantine of ties, often with testing frequency proportional to with detection of infections in schools. In univer- classes, cohorts, or close contacts in response to on-campus activity. Implementation in elemen- sities, it has been used in student residences an in-school exposure. A cluster randomized trial tary schools and high schools has been shown and supported identification of asymptomatic suggests test-to-stay is not inferior to quarantine to increase case detection and highlighted that individuals, limiting outbreak potential. after in-school exposures, and a retrospective many infections were community acquired, study identified no difference in case rates after Potential challenges/limitations. Although rela- underscoring the potential value of the strategy. implementation of the strategy. Additionally, up to tively low-cost on a “per-person covered” basis, eight in-person school days could be preserved for Potential challenges/limitations. The costs of this tool relies on necessary infrastructure being asymptomatic, negative-testing students through PCR and even antigen tests for universal serial available to support precise surveillance. Testing implementation of this strategy, compared to a testing are high, with additional costs associated of wastewater samples must be frequent enough 10-day quarantine. with logistics. Costs may be reduced through to establish a baseline and to identify surges. It self-testing, although this may result in lower also necessitates that students, teachers, and Potential challenges/limitations. This strategy quality specimens and impact test accuracy. staff use bathroom facilities (difficulties may generally relies on symptom-based detection of Consistent adherence with the testing schedule arise in childcare centers where young children an index patient, and approximately one third of may also be a challenge. might not be using the bathroom facilities). all infections are asymptomatic. During periods of high community spread, resources required to implement it will also increase. References: Nemoto et al. 2021; Harris-McCoy et al. 2021; Young et al. 2021; Corchis-Scott et al. 2021; Crowe et al. 2021. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 28 The Testing Armamentarium Different types of tests can be used to detect either current or previous infection. All have roles to play in gathering SARS-CoV-2 surveillance data and informing reactive and proactive measures. Tests for current infection include reverse transcription polymerase chain reaction (RT-PCR) and rapid antigen tests. Tests for current infection can provide data on changes in epidemiology, informing reactive measures to any changes. Additionally, when used serially, they can help predict how SARS-CoV-2 epidemiology may change in the future, proactively informing measures that should be implemented. When used in this way, these tests can provide additional data on how mitigation measures are working and whether measures should be increased, continued, or scaled back. As discussed in previous sections, specimens taken for PCR testing can readily be subjected to genotyping or sequencing to identify known variants or new mutations—contributing to local, national, and global genomic surveillance efforts. Tests for previous infection include antibody tests. They can provide data on how different mitigation strategies have worked to protect popula- tions from infection and to monitor population-level immunity. They can help inform future mitigation strategies and inform future scheduling of SARS-CoV-2 vaccines based on changing population immunity. Table 3 describes fours types of tests, the information they provide, their advantages and disadvantages, and their costs8 (Simonetti et al. 2021). Photo credit: U.S. Pacific Fleet 8  UNICEF. UNICEF Supply Catalogue. Available: https://supply.unicef.org/. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 29 Table 3. Breakdown of the Four Types of SARS-CoV-2 Testing Characteristic PCR Antigen Antibody Genotyping/Sequencing Laboratory-based PCR Collected and assessed by point-of- Laboratory-based antibody detection Various platforms to support Types of care health care worker virus genotyping and technologies Point-of-care PCR (using loop Point-of-care antibody detection (by sequencing mediated isothermal amplification Point-of-care self-collected and health care worker or self-test) available [LAMP] technology) assessed Presence of SARS-CoV-2 above Presence of SARS-CoV-2 antigens Presence of IgG and/or IgM Presence of target mutations the lower limit of detection of the above the lower limit of detection antibodies; may also detect presence and or whole genomes, assay (typically encompassing of the assay (typically only of specific S- and N-antibodies, which can be compared to Information the preinfectious, infectious, and encompassing the infectious period) to support vaccine-acquired vs. identify target mutations for provided postinfectious periods) infection-acquired immunity further investigation Information is qualitative (positive vs. Information can be quantitative or negative) Information can be quantitative or Information is qualitative qualitative qualitative ~$20 per patient (clinical samples) for ~$5 for the test device; additional ~$10 for materials and reagents for ~$40 per sample, if sufficient materials and reagents; personnel costs associated with health care laboratory-based detection volumes of samples costs potentially reduced through worker collection, assessment, and are collected and run pooling or noninvasive sample recording, if necessary ~$5 for point-of-care test device; simultaneously Costs ($US) collection additional costs associated with health care worker collection, $300 per test (wastewater samples), assessment, and recording, if equivalent to <$0.30 per patient if necessary population covered is >1000 Highly sensitive and specific Inexpensive to manufacture and Simple to use and generally Can be leveraged with a diagnostic; gold standard method distribute; very sensitive during the inexpensive; can be used with a variety of specimen types; for SARS-CoV-2 detection; can be infectious period of infection; can variety of specimen types; may help can provide a view into leveraged with a variety of specimen be used at the point of care and via prioritize persons for vaccination circulating variants in the Advantages types (for example, nasopharyngeal, self-testing—improving access and when supply is limited community and identify new oropharyngeal, nasal, saliva, enabling more people to be tested mutations gargle)—each of which has different access, acceptability, and cost considerations Generally, requires sophisticated Test conduct and interpretation Limited utility on an individual level; Generally, very expensive laboratory infrastructure; subject to user error; not very antibodies tend to wane over time on a per-specimen basis; comparatively expensive and time sensitive early in infection and will especially among older age groups requires sophisticated consuming; collection, transport, miss infections PCR will detect; high and the immunocompromised, laboratory infrastructure and Disadvantages preparation, analysis, and specificity, but positive predictive thereby limiting the temporal value analytic capabilities communication of results may take value ~50%–70% at lower levels of of tests upwards of 48 hours in overburdened circulating virus labs; may miss infections in the first day or two after infection The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 30 Surveillance Case Examples Six case examples, including one each from Argentina and Uruguay, illustrate passive and active surveillance approaches are being used for SARS-CoV-2 prevention and control. United Kingdom’s Representative Population Survey These repeated cross-sectional surveys provide critical data. These data allow estimation of prevalence and seroprevalence at national Context. Repeated testing for current and previous infection in a repre- and subnational levels, and they can be stratified by participant sentative population sample to estimate prevalence of SARS-CoV-2 characteristics such as age, sex, and occupation, allowing targeted (current infection) and seroprevalence of SARS-CoV-2 (previous infec- public health approaches to be employed. As vaccination programs are tion) in the UK. rolled out, this method can further support monitoring and evaluation of Situation overview. In April 2020, the University of Oxford, along with the impact of vaccination programs on the immunity of the population. multiple government agencies and other universities, began recruiting As the pandemic has continued, these data provide insight into changing participants in England—later expanding to Wales, Northern Ireland, transmission and reinfection risks, and a robust sequencing platform and Scotland—for SARS-CoV-2 infection surveillance to estimate supports monitoring for variants. Finally, such comprehensive data the prevalence of SARS-CoV-2 in the United Kingdom. This included support public health officials in forecasting and modeling, supporting repeated sampling to detect current infection and previous infection proactive—rather than reactive—decision-making. among randomly selected households intended to be representative of Challenges and lessons learned. The survey has encountered the UK population. challenges with respect to recruitment and retention of participants. This ongoing effort aimed for a target population of 179,000 participants Given the number of tests needed from each participant, people (two years of age and older) each fortnight from randomly selected are increasingly lost to follow-up as the study continues. Another private households across the UK. To estimate the positivity rate of challenge has been the high cost of PCR testing and the need to SARS-CoV-2 (even in asymptomatic cases), each participant was asked have specialized centers to process the samples. Pooling of samples to complete a monthly survey and provide weekly nose and mouth swab can save some resources during periods of low prevalence, but this tests for the first five weeks, followed by monthly swabs for a year. In becomes increasingly inefficient as prevalence increases. The initiative addition, a subset of the positive swab samples underwent genomic exemplifies the value of collaboration between the public, private and testing. Finally, a smaller subset of participants aged 16 and older academic sectors for implementing testing and surveillance strategies. provided blood samples to analyze antibodies from past infections. The It also highlights the importance of longitudinal studies (that can make data collected are published weekly in public reports. As of April 2022, repeated observations over time) to characterize the epidemiology of recruitment targets were reduced by ~25 percent per fortnight. SARS-CoV-2 and understand its changing impact on the population. As vaccine rollout started, the approach was adapted to reflect new References: realities of population immunity. The serosurveillance program increased Office for National Statistics. Coronavirus (COVID-19) Infection Survey: Methods and 1.  the percentage of blood samples from participants aged 16 years and Further Information. United Kingdom. Available: https://www.ons.gov.uk/peoplepop- ulationandcommunity/healthandsocialcare/conditionsanddiseases/methodologies/ older, and subsequently included samples from children five years and covid19infectionsurveypilotmethodsandfurtherinformation. older. In addition, the reports began including summaries from genomic 2. COVID-19 infection survey of the UK general population (ISRCTN21086382). ISRCTN surveillance as well as reinfection data. Registry. Available: https://www.isrctn.com/ISRCTN21086382. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 31 Surveillance Case Examples Slovakia’s Country-Level Rapid Antigen Testing Population-wide antigen testing identified people with infection, and their own and their contacts’ self-isolation, coupled with country-wide Context. Multiple rounds of population-wide rapid antigen testing, with restrictions, appears to have substantially contributed to slowing isolation and contact tracing to control SARS-CoV-2 in a country with a transmission. This case example demonstrates how testing can play a population of 5 million people. role in a country’s larger public health response. Proactively leveraging Situation overview. Before the summer of 2020 in Slovakia, daily cases the data collected to target subsequent rounds of testing and conducting of COVID-19 were below 100 per day. In August 2020, cases started to an epidemiologic analysis of the resultant data to understand drivers of precipitously increase. As a result, restrictions in the country grew to transmission reduction provide critical information for the public health include no outdoor gatherings and early closure of restaurants. On response moving forward. October 1, 2020, the government declared a state of emergency for 45 Challenges and lessons learned. Although the rollout of rapid antigen days and increased restrictions in the country even further. However, tests can be highly efficient, fast, and associated with a lower cost on COVID-19 cases continued to rise, with around 2,000 new cases per day a per-test basis than PCR testing, the approach in Slovakia also faced by mid-October. several challenges. Contrary to jurisdictions where antigen tests are As the situation worsened, Slovakia began evaluating population-wide self-performed, such as the United Kingdom, in Slovakia the samples testing using rapid antigen tests while applying lockdown restrictions. are collected by medical personnel, which presents barriers in terms of People testing positive, their household members, and any contacts in the human resources and costs. Second, rapid antigen tests typically have previous two days would need to quarantine. A pilot study was conducted positive predictive values in the range of 50 percent to 70 percent at in late October 2020 in four counties with the highest prevalence of SARS- lower prevalence, so the risks of incorrectly isolating individuals need CoV-2. In the subsequent two weeks, these counties were tested a second to be considered. Finally, rapid antigen tests are best suited for use and third time. The success of the pilot study led to national mass testing. as a screening test—not a diagnostic like PCR—as sensitivity is low After an initial round of testing, counties with the highest prevalence were in early and late stages of infection, but generally much higher during tested a second time. Overall, around 60 percent of the total population infectious periods. was tested during this period—representing about 80 percent of the References: eligible population aged 10 years and older. Reuters Staff. Slovakia Reports Record Spike in Coronavirus Cases. 2020. Available: 1.  In the weeks following the testing campaign and the imposed restric- https://www.reuters.com/article/us-health-coronavirus-slovakia-idUSKBN25W0I5. tions, the prevalence of SARS-CoV-2 decreased significantly. Between 2. Pavelka M, Van-Zandvoort K, Abbott S, et al. 2021. “The Impact of Population-Wide Rapid Antigen Testing on SARS-CoV-2 Prevalence in Slovakia. Science 372: 635–41. the pilot phase and the first round of country-wide testing, the prev- alence decreased by 56 percent; after the targeted second round of testing in high-prevalence counties, prevalence further decreased by 60 percent. Overall, the total decrease in prevalence was estimated to be 82 percent, with minimal variation across Slovakia. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 32 Surveillance Case Examples Population-Wide Surveillance in Rotterdam, • Identification of undertesting in one city area. In response, the program added 10 clinical testing locations including the use of the Netherlands mobile “test buses” to improve access. Context. Population-wide testing in a European city with a population • Additional evidence. Local authorities value an assessment of of 400,000. COVID-19 status in city areas that is independent of clinical tests or syndromic surveillance. Situation overview. The Dutch are leaders in wastewater-based surveil- Challenges and lessons learned. Rotterdam’s program initially faced lance and were one of the first settings to isolate SARS-CoV-2 in waste- challenges with its supply chain for wastewater collection and testing; water. Wastewater testing in Rotterdam began as a research project the complex data analyses that involved examining and correlating to identify its added value and assess whether detected SARS-CoV-2 both clinical and wastewater test results; and the limited number of reflected clinical COVID-19 infection. Six local and national partners wastewater collection sites located across the city, which did not allow collaborated closely on testing, interpretation, and public health action. a surveillance of the complete city in high resolution. Early success showed that wastewater surveillance reliably identified SARS-CoV-2 before clinical case resurgence, and the program was inte- Key lessons learned are that success depends on these factors: grated into public health practice. • Collaboration between local public health and water authorities Wastewater testing is performed three times each week at nine waste- • Normalization of clinical data for test delays and number of tests water sites: four pumping stations and five treatment plant influents of different city areas. A careful match was made via zip codes with the • Normalization of sewerage data for flow and population population served and the clinical surveillance data. Wastewater and • Continuous evaluation of sewerage data versus incidence data clinical test results are analyzed after adjustment for sewage flow and • Frequent sampling to support trend analysis of the normalized population, and clinical tests are adjusted for test delays and the number SARS-CoV-2 concentration in wastewater of tests. Models of wastewater data were developed by comparing Reference: results to wastewater tests. The city continues to monitor COVID-19 1. https://storymaps.arcgis.com/stories/8888f5bfb4704180afeda3d476f2aa63. using both clinical and wastewater surveillance. Value in surveillance strategy. Wastewater surveillance provides Rotterdam with valuable information beyond what clinical testing can provide. Benefits of added value include: Photo credit: Pouw Vervoer • Early identification of resurgence. In September 2020, wastewater surveillance provided a six-day advance warning. Since then, clinical testing increased, and by December 2020 the advance warning narrowed to 1.5 days. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 33 Surveillance Case Examples Genomic Surveillance in South Africa: from over 30 different clinics in Gauteng; (2) examine the surge of cases and the positivity rate; (3) upload the genome to a regional data base Detecting Omicron (this pointed to the variant first being identified in Botswana); and (4) Context. Genomic surveillance as an integral part of SARS-CoV-2 disseminate the information, allowing global research to be conducted surveillance in South Africa. to understand transmissibility, virulence, and immune evasion characteristics of the variant and give other countries time to prepare Situation overview. Scientists in South Africa have pioneered the for the new surge. discovery of two variants of concern, beta (B.1.351) in September 2020 and omicron (B.1.1.529) in November 2021. Genetic sequencing for Challenges and lessons learned. Genomic testing has shown to be SARS-CoV-2 in South Africa began in May 2020 with the creation of the an important component of testing strategies during the COVID-19 Network for Genomic Surveillance (NGS-SA) and a goal to sequence pandemic, and the WHO recommends that 5 percent of all processed several thousand genomes to inform public health responses. samples should undergo genomic testing. This will necessitate investment to create networks, share data and protocols, and train By December 2021, over 24,000 genomes had been sequenced across teams. Speed and transparency in identifying and reporting new seven sequencing centers, accounting for over 40 percent of all mutations should be prioritized and supported—practices that penalize sequences published in Africa. To ensure that samples are processed in jurisdictions for doing so will discourage transparency and may prolong a timely manner, each laboratory partners with a neighboring academic the pandemic. sequencing center. To track and detect new variants, the NGS-SA established a process to collect the samples based on a random sample References: approach. This approach uses ongoing surveillance to create represen- European Centre for Disease Prevention and Control. SARS-CoV-2 Variants of 1.  tative samples of the geographical spread of the virus across South Concern. Available: https://www.ecdc.europa.eu/en/covid-19/variants-concern. African provinces. 2. Msomi N, K. Mlisana, T. de Oliveira, et al. 2020. “A Genomics Network Established to Respond Rapidly to Public Health Threats in South Africa.” The Lancet Microbe 1: In 2020, early in South Africa’s second wave, the beta variant was discov- e229–30. ered. Less than 48 hours after the discovery, a public health response 3. WHO. 2021. Scaling Up Genomic Sequencing in Africa. Available: https://www.afro. in the form of increased restrictions was made. This rapid response was who.int/news/scaling-genomic-sequencing-africa. repeated when the delta variant was identified in the country. 4. WHO. 2021. Why Genomic Sequencing Is Crucial in COVID-19 Response. Available: https://www.afro.who.int/news/why-genomic-sequencing-crucial-covid-19-response. In November 2021, COVID-19 cases started to rise in Gauteng province. 5. P. Adepoju. 2021. Why South Africa Keeps Detecting COVID-19 Variants By the end of the month, genomic surveillance had increased in the Like Omicron. Devex. Available: https://www.devex.com/news/ why-south-africa-keeps-detecting-covid-19-variants-like-omicron-102212. province, and, shortly after, six samples with a highly mutated genome 6. I. Chotiner. 2021. “How South African Researchers Identified the Omicron Variant of were discovered. To determine the spread of these mutations and COVID.” The New Yorker, November 30, 2021. Available: https://www.newyorker.com/ facilitate research into this variant, the NGS-SA proactively proceeded news/q-and-a/how-south-african-researchers-identified-the-omicron-variant-of-covid. to (1) test the genome of more than 100 randomly selected samples The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 34 Surveillance Case Examples Country Case Example: Argentina area. People who tested positive were asked to isolate and offered neces- sary care, while their close contacts were monitored daily for two weeks. Context. The first case of SARS-CoV-2 was reported in Argentina on Since April 2022, a new epidemiological surveillance strategy for acute March 3, 2020. A strict national lockdown was enacted early in the respiratory infections is being implemented with the aim of monitoring pandemic, and a comprehensive preparedness and response plan was the frequency and distribution of SARS-CoV-2, influenza, RSV, and other formulated. However, after the lockdown was eased, cases precipitously respiratory viruses, as well as characterizing their severity and impact on increased and as of the end of 2021, over 5.3 million cases had been the population. Therefore, COVID-19 testing is only prioritized for people detected with over 116,000 deaths. The omicron variant—first detected with respiratory symptoms belonging to specific at-risk groups in early December 2021—presented new challenges, but progress made in the vaccination campaign reduced the impact on mortality Successes and challenges. The initial rapid response to the first cases and hospitalization in intensive care units. Since mid-November 2022 of COVID-19 in the country, coupled with decentralization of testing to build capacity and implementation of targeted testing and surveillance, new confirmed COVID-19 cases started to increase again, with almost was a clear success in Argentina’s national response. The challenge in 27,000 new cases during the first week of December 2022 (a 115 percent the current epidemiological context, characterized by a lower severity of increase in one week). As of December 2022, over 9.7 million cases COVID-19 cases and the increase circulation of other respiratory viruses, had been detected with over 130,000 deaths, while approximately 83 is to implement a transition strategy which includes a comprehensive percent of the population was considered fully vaccinated. approach to respiratory viruses, strengthening epidemiological surveil- Testing and surveillance. By the end of March 2022, 35 laboratories lance to monitor both the impact of COVID-19 on at-risk groups and the across the 24 provinces in Argentina were able to perform PCR testing. population, and the changes that may necessitate a modification in the In April 2020, a special committee of medical and scientific experts was approach to COVID-19 control. formed, to provide advice and guidelines to health authorities for the design of policies to address the pandemic, including testing and surveil- References: lance. These policies were later implemented by the federal ministers of National Decree 297/2020: https://www.boletinoficial.gob.ar/detalleAviso/ 1.  health through the Federal Council of Health (COFESA). primera/227042/20200320. 2. National Decree 260/2020: http://servicios.infoleg.gob.ar/infolegInternet/anexos/335000- Testing for COVID-19 was initially offered to all those with symptoms 339999/335423/norma.htm. of COVID-19, with close monitoring offered to contacts. As cases rose, 3. https://www.argentina.gob.ar/noticias/ testing criteria had to be modified to preserve laboratory capacity. Testing anlis-avanza-en-la-descentralizacion-de-la-deteccion-diagnostica-del-nuevo-coronavirus. 4. https://www.lanacion.com.ar/sociedad/ criteria varied across provinces. When outbreaks were identified or when coronavirus-diagnostico-malbran-laboratorios-35-mil-reactivos-nid2348572/. increases in the number of cases in an area were recognized—particularly 5. https://bancos.salud.gob.ar/recurso/instructivo-para-la-notificacion-de-caso-covid-19. in lower socioeconomic areas—close surveillance was implemented, with 6. https://bancos.salud.gob.ar/sites/default/files/2020-11/Guia-Operativa-Detectar-10-11-2020.pdf. active efforts to identify cases through the “Dispositivo Estratégico de  omprehensive surveillance and control strategy for COVID-19 and other acute respiratory 7. C Testeo para Coronavirus en Terreno Argentino” (DETECTAR). This involved infections: https://bancos.salud.gob.ar/sites/default/files/2022-04/2022-Estrategia_IRA%20.pdf volunteers and community health care workers visiting households in the The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 35 Surveillance Case Examples Country Case Example: Uruguay The primary strategy for testing and surveillance focused on the widespread availability of testing through COVID-19 assessment centers, Context. Uruguay started to prepare for the pandemic as early as aggressive contact tracing, targeted testing in outbreaks, enhanced January 2020, with measures such as border control, the creation of a testing approaches around the border, and use of sentinel- and hospital- contingency plan, and the training of the Department of Public Health based surveillance. However, as cases increased, testing and surveillance Laboratory. On March 13, 2020, Uruguay confirmed its first case of policy has shifted. From the beginning of 2022, PCR and antigen testing is SARS-CoV-2; it was successful in managing the population impacts limited to symptomatic people from selected population and risk groups. throughout 2020—with only 180 total deaths. However, the emergence of the more transmissible gamma variant in 2021 led to increases in cases Although started independently by several organizations, genomic far beyond what could be managed by existing contact tracing systems, surveillance was centralized through the creation of the Interinstitutional and by the end of 2021 the death toll exceeded 6,000. Though Uruguay Working Group (GTI) on Surveillance of SARS-CoV-2. The aim of this went through a new wave led by the highly transmissible omicron variant group is to centralize and monitor real-time genomic information for in 2022, deaths by December 2022 stand at ~7200 and 82 percent of the SARS-CoV-2 across the country. GTI is comprised of seven different population is considered fully vaccinated (two doses). institutions, including IP, Universidad de la República and the Ministry of Public Health, that receive around 100 specimens each week from Testing and surveillance. Testing and surveillance strategy design and the public diagnostic network and other groups. evaluation are the responsibility of the “Honorary Scientific Advisory Group (GACH),” a group that was created on April 16, 2020, to provide Successes and challenges. The establishment of ad hoc advisory advice to the government on the COVID-19 emergency response. The groups composed of multidisciplinary experts to guide testing and team includes 55 multidisciplinary science experts forming three divisions: surveillance policy and coordinate genomic surveillance in the country, the technical secretariat, the scientific health team, and the data team. together with the use of locally developed and distributed test kits, In addition to its responsibilities on testing and surveillance, the GACH resulted in a successful national response to the COVID-19 pandemic makes scientific recommendations in the areas of health and data science in Uruguay. However, key challenges still exist, and testing and surveil- to the government team, which evaluates and submits the reports and lance strategies can still be improved, through approaches such as suggestions to the president of the republic for final decision-making. wastewater-based surveillance, which has been piloted in Uruguay. Recommendations from the GACH are implemented by the Ministry of References: Public Health through the Directorate of General Health. 1. https://www.gub.uy/ministerio-salud-publica/institucional/normativa/ordenan- za-n-85022-actualizacion-criterios-para-testeo-manejo-del A major reason for Uruguay’s early success in the pandemic was its 2. https://www.gub.uy/ministerio-salud-publica/sites/ministerio-salud-publica/ “made-in-Uruguay” PCR tests, developed at the Instituto Pasteur, files/2022-04/Resoluci%C3%B3n%20512%20022%20-%20Actualizacion_criterios__ with the support of the Universidad de la Republica. Test production testeo_y_cuarentena_covid_-_abril_2022.pdf and distribution were bolstered through the creation of the “COVID-19 diagnostic lab network.” This network shared technical knowledge with research institutes, public hospitals, and academic laboratories from all around the country, supporting rapid scaling of testing capacity. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 36 4 Toward a Proactive Approach to National Testing and Surveillance Overview of the National Testing and Surveillance Program Cycle Photo credit: Henitsoa Rafalia / World Bank The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 37 Figure 12. Phases of the National Testing and Surveillance Program Cycle As we enter the fourth year of the COVID-19 pandemic, national testing 1 and surveillance programs remain essential for countries worldwide— including those in Latin America and the Caribbean. With the availability of low-cost testing and surveillance tools, global vaccination and Assess existing therapeutics, and the need to monitor emerging variants, national surveillance approaches testing and surveillance programs will necessarily need to shift with the and available resources current context and epidemiology. Consider: What do you currently know? What don’t you know? For all countries, the process of designing a national testing and surveil- ? lance program is cyclical, with four key phases (figure 12): 4 2 ? 1) Assess existing surveillance approaches and available resources. 2) Consider priorities (goals, objectives, and outcomes) and Evaluate the strategy, adapt develop a preliminary strategy. it, and renew the cycle Consider priorities and 3) Engage stakeholders to refine, optimize, and implement the Consider: What worked in the develop preliminary strategy strategy. first implementation cycle? Can Consider: Will your program focus you ensure the data are used and on a broad population or specific 4) Evaluate the strategy, adapt it (based on findings and new communicated more effectively? groups, or both? realities), and renew the cycle. National testing and surveillance programs will vary country to country 3 depending on available resources, priorities, and epidemiologic context. Countries with low case counts and high rates of vaccination will have national testing and surveillance programs that are likely to differ from Engage stakeholders those in countries grappling with emerging COVID-19 waves and/or with to refine, optimize, and implement the strategy limited access to vaccines and therapeutics. Despite these differences, Consider: Who will lead the program? the implementation phases of national testing and surveillance programs Is lab capacity adequate? are identical, providing a framework for all countries to follow. For each implementation phase, the planning processes will be informed by: It is key to consider how testing and surveillance data can be proactively • The types of testing and surveillance infrastructure and programs leveraged to add value to the current national strategy and how existing already implemented testing and surveillance systems can be adapted to support the • The country’s capacity to replace, expand, or add testing and surveil- implementation of more active methods. Thinking about the strategy as lance programs within its health system a cycle—rather than as a static, one-time process—emphasizes the need • The country’s ability to successfully implement these programs and to stay nimble and responsive to the changing landscape of the pandemic. proactively leverage such data to inform public health responses The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 38 Phases of a National Testing and Surveillance Program Phase 1 — Assess Undertake a comprehensive inventory of your existing and emerging 1 testing and surveillance approaches and resources and how they fit within your overall surveillance approach. Identify your gaps and needs. Prior to starting or expanding a national testing and surveillance strategy, 4 2 Assess Phase 1 it is important to take a comprehensive inventory of your country’s current testing and surveillance activities and capacity. This assess- 3 ment can help elucidate emerging tactics and how they may fit within Overall surveillance your country’s broader approach to surveillance and existing resources. approach within public This will further identify current areas of weakness and blind spots (data health response gaps). It is helpful to consider this inventory with two key questions in mind: What is the country’s overall approach to SARS-CoV-2 surveil- Current surveillance lance? How would implementing additional testing and surveillance inventory approaches complement the current surveillance strategy and support proactive public health responses? There are five key areas to consider: (1) the overall surveillance approach Human resource within the broader public health response to SARS-CoV-2; (2) a current inventory inventory of surveillance data; (3) a current inventory of human resources and capacity; (4) a current inventory of laboratory, information, and Laboratory and analytic systems; and (5) an inventory of political and public receptivity. information systems These foundational considerations will help guide assessments of inventory other areas, supporting the stepwise implementation, improvement, and sustainability of new approaches within national testing and Inventory of political and surveillance strategies. public receptivity The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 39 4 2 3 Overall Surveillance Approach Within Public Health Response What is your country’s approach to using different methods of surveillance to support the public health response? Beyond measuring the current or previous burden of SARS-CoV-2 infec- Implementation of active testing and surveillance approaches can tion, comprehensive public health responses leverage multiple other provide information beyond who is currently or was previously surveillance metrics to inform an overall strategy. These other metrics infected. Active approaches also provide critical information that may include: measuring the direct and indirect health consequences of supports several other aims that an overall surveillance program the pandemic, monitoring public health interventions, monitoring social may have. Articulating your overall surveillance strategy will help you and behavioral trends, and monitoring epidemiologic trends in SARS- transparently assess how new testing and surveillance approaches CoV-2 (table 4). can be proactively leveraged. Table 4. Other Surveillance Metrics to Inform Overall Approach Measuring the direct and indirect health consequences Monitoring public health Monitoring social and Monitoring epidemiologic of the pandemic interventions behavioral trends trends in SARS-CoV-2 Hospital-based surveillance, which • • Vaccine uptake and coverage  ocial determinants of SARS-CoV-2 •S Modeling to inform both short- and • includes the number of COVID-19 infection long-term forecasts patients in hospital, overall  opulation mobility and social •P utilization, and existing capacity interactions • Vaccine hesitancy • Transmission dynamics Mortality-based surveillance, which • • Adherence to and acceptability of Willingness and ability to follow • Health inequities • includes the number of people dying nonpharmaceutical interventions public health measures from COVID-19 (diagnosed and Correlates of protection • undiagnosed) and excess mortality Uptake and access to COVID-19 • Trust in science and the government • associated with unintended therapeutics • Vaccine effectiveness with consequences of the pandemic  nemployment rates, food and •U respect to preventing infection, housing insecurity, poverty symptomatic disease, • Monitoring mental health and well- hospitalization, and death and being indicators assessing waning protection over time Monitoring continuity of essential • health services and wait times for Variant-of-concern assessments (for • health care example, transmissibility, virulence, immune evasion, and vaccine • Monitoring rates of COVID-19 effectiveness) recovery and long COVID The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 40 4 2 3 Surveillance Data Inventory Figure 13. Considerations to Support the Selection of What are the weaknesses and gaps in your current Surveillance Approaches approach to surveillance? Timeliness It is helpful to place your current methods of collecting data on levels of Are there delays in reporting of testing or surveillance current and previous SARS-CoV-2 infection in the context of the overall data? Have current approaches to testing and goals of your SARS-CoV-2 surveillance. Consider your previous experi- surveillance missed outbreaks or surges or identified ence during this pandemic and the experience of other countries to enrich them too late? your overall assessment. Use this exercise to develop a blueprint of: Population-wide surveillance • Which goals you are currently achieving Do you have current gaps in testing coverage? If a surge of infections were to occur, do plans and capacity exist • Which goals you are not currently achieving to accommodate a response? Will proactive approaches support your public health response? • Which goals you would like to prioritize moving forward Targeted surveillance Are common SARS-CoV-2 hotspots (such as health Within the context of fiscal space considerations, consider how imple- care settings, congregate settings, certain workplaces, menting additional approaches to testing and surveillance could work to low-income neighborhoods) known? Are surges in cases address the current gaps and weaknesses in your current strategy. With in these hotspots easy to identify? Are the populations the resources you have available, consider the ranking of the goals you impacted difficult to reach? have prioritized moving forward—which surveillance approaches might be feasible immediately and which might require further investment? Available resources Are there available resources (expertise, financial, To support this exercise, consider your current testing and surveillance system with the following elements in mind (figure 13): $ human resources, lab capacity) to expand your surveillance approach? Are there efficiencies that • Timeliness could be made to free resources? Which resources are “fundamental” to your overall approach? • Population-wide surveillance Variants of concern • Targeted surveillance Do you have current gaps in understanding circulating • Available resources variants of concern in the country? Do you have local capacity or access to international capacity to perform • Variants of concern sequencing on SARS-CoV-2 specimens to estimate the spread and prevalence of variants of concern? The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 41 4 2 3 Human Resource Inventory completeness, utility, and potential limitations of data generated by Who is needed to implement, analyze, communicate, and existing information systems. Beyond this, national testing and surveil- oversee your approaches to testing and surveillance? lance approaches require knowledgeable analysts who can work effi- ciently and in parallel with communicators for rapid dissemination of A national testing and surveillance strategy is human resource inten- findings to both stakeholders and the public. sive. It requires a diverse group of individuals with different areas of expertise in the right numbers and, importantly, these groups must Several potential issues in laboratory and information systems warrant work together efficiently. The scope and scale of human resources particular attention. For example, it may be important to reflect on how needs to be actively monitored and managed within the ever-changing such systems are structured (for example, are information systems context of national strategies. interoperable, with the ability to link different types of testing and surveillance data?), how quickly test results and surveillance reports are Review the human resources you can leverage as part of an expanded generated, how completely and efficiently data are transferred between testing and surveillance strategy (for example, consider the potential public and private partners and health system levels, what current for task shifting). Key groups include implementing partners, laboratory protocols for data protection and privacy exist, and which data quality personnel, data managers, data communicators, logistics supply chain) assurance and improvement processes are implemented. Overall, a experts, health care personnel, and scientists. Who will be involved, comprehensive understanding of the capacity limitations in existing and in what capacity, will be determined in the development phase, but laboratory and information systems is essential to begin to address assessing what is feasible early on is imperative. such issues and optimally use data gathered from proactive testing and surveillance approaches. Laboratory and Information Systems Inventory Which laboratory, information, and analytic systems are Inventory of Political and Public Receptivity required to support implementation and data collection, How ready for and receptive to new approaches to testing analysis, interpretation, and communication? and surveillance are the government and the public? National testing and surveillance approaches require reliable and inte- The success of any surveillance program relies on buy-in not only grated infrastructure to ensure data arrive in the right hands in a timely from government departments and political organizations, but also manner. In the case of testing, this requires efficient sample transporta- from members of the health care system, private industry, and the tion networks and strong supply chains for materials required by labo- public. Moreover, depending on the current structure of testing and ratories and for the tests themselves. A key consideration—particularly surveillance system governance, institutional responsibilities around when considering PCR testing—is understanding the lab capacity that managing surveillance systems could lie at various levels of government. is currently used and lab capacity that could be leveraged elsewhere. Understanding who needs to be brought to the table and engaged during For forms of surveillance less reliant on testing (such as mortality-based the design and implementation of new testing and surveillance activities or wastewater-based surveillance), this inventory should consider the is crucial for their success. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 42 As with any new program, stakeholders will want to know the potential risks and benefits associated with implementing new approaches to testing and surveillance, as well as how their value compares to already existing programs. Some stakeholders may be sensitive to added costs associated with increased testing and surveillance, may be concerned with the incremental benefits that can be obtained, or may have valid ethical concerns about how such programs would be implemented and data proactively used for decision-making. In the assessment stage, it is important to understand the various sensitivities and concerns from the stakeholders involved so that potential issues can be addressed accordingly. For the public, it is important to transparently communicate the rationale and value added by these new testing and surveillance approaches. The scientific basis for the new approaches needs to be clear, as well as how the data will be proactively leveraged to inform the public health response. If members of the public are being asked to take on tasks themselves (such as self-testing), transparency is all the more important, and special consideration should be given to how logistical barriers will be addressed and access supported. Public media campaigns with clear messaging are one method to try and achieve this. Informing the public and stakeholders at the outset on how different approaches will be measured in terms of their added value or utility, and subsequently communicating how successful these approaches were in achieving their desired goal, will build trust in the process. Photo credit: Diverse Stock Photos The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 43 Phases of a National Testing and Surveillance Program Phase 2 — Develop Consider priorities and develop a preliminary program 1 The assessments completed in phase 1 should make clear the major goals of your country’s overall surveillance approach. In line with these goals, 4 2 the development phase articulates the priorities and objectives of the Develop Phase 2 surveillance approach, highlights the key personnel that will be required to implement your approach, reveals key implementation areas to address, 3 helps you estimate required resources, and allows you to plan implemen- tation in such a way that results will inform public health response. Set goals and objectives Set Goals and Objectives Following national goals for SARS-CoV-2 testing and surveillance, develop your overall priorities for new testing Gather your team and surveillance approaches and how their data will be proactively used. Obvious goals will be to reduce the incidence of SARS-CoV-2 nationally and particularly within disproportionately affected groups. However, Consider these key consider other goals as well, including earlier identification of future waves implementation questions of infection, reduced laboratory burden, better targeting of public health measures, identification of populations for vaccination or revaccination efforts, capacity to maintain essential health services, and identification Estimate costs and of emerging mutations. Recall that active surveillance approaches can required resources provide a wealth of data, and how you wish to proactively leverage data collected from such approaches should be clear. Organize your goals into short-, medium-, and long-term objectives for your surveillance program, Ensure results will inform which will make clear what you hope to achieve in a measurable fashion. public health action Although implementing new surveillance approaches is highly useful, these tools are not silver bullets and cannot replace robust public health responses to the pandemic. Remember, these new approaches: • Complement other testing and surveillance approaches and do not remove the need for other public interventions. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 44 4 2 3 • Take careful planning and may require sophisticated infrastructure • Steering or advisory structures. Are there groups of experts that can take time to develop. and stakeholders to determine the overall program direction and whether its goals are being reached? • Can provide various types of information that should be interpreted according to local context and epidemiology, rather than in a vacuum. • Implementation structures. Which organizations, personnel, and other stakeholders will be involved, and what will their responsibili- • Represent a future investment in public health infrastructure. The ties be? How will the correct groups be linked with each other during platforms necessary to implement many testing and surveillance implementation? How will support from each implementing partner approaches are readily translatable to many other public health issues. be gathered? With your goals and objectives in mind, begin also to develop how you will assess the success of your strategy—in the short, medium, and long • Reporting and public health action structures. How will different terms. Success may mean different things in different contexts but should findings and reports from your surveillance program be commu- be clear and measurable. By developing such an evaluation plan early on, nicated and to whom? How will different testing and surveillance you are in a better position to identify implementation challenges early, approaches be proactively used to make decisions on the public increase the likelihood that your surveillance program will provide the data health response? Are the correct groups and structures in place to you need, and improve its overall quality. support said response? Gather Your Team Consider Two Key Implementation Questions Identify the personnel who will be needed to implement What population will you sample, and how often? your testing and surveillance strategy. This may include Active testing and surveillance approaches can be targeted to specific people involved directly with implementation, with the laboratory system, populations or locations, can be population-wide, or both. Although with data management, with the supply chain, with different health contact tracing and testing are an essential public health tool, local care sectors, with the private sector, and with different governmental realities may mean that decisions on where this approach can be imple- agencies (see Phase 3 — Implement, for more detail). mented fully will need to be made. Similarly, although genomic surveil- Review the overall surveillance program’s support structures. Will lance may leverage passively collected samples and is highly useful, rearrangement or new roles be required with implementation of new it is resource intensive. Reaching a WHO-recommended threshold testing and surveillance approaches? Ensure all involved have clarity on for the proportion of specimens sequenced may not be possible, and their roles and agree to their responsibilities. Consider: if genomic surveillance is implemented, it will be important to clearly define which specimens will be sequenced. The frequency of testing will • Accountability structures. Who is responsible for decision-making also need to be decided upon, depending on the approach, such as for and oversight at different levels of the surveillance program? Who is representative population surveys and serial testing. It is critical to make taking ownership of different forms of surveillance? these decisions in the context of existing resources and the potential for The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 45 4 2 3 changing operating conditions. Therefore, strategies should be flexible • Transportation networks. Critical to effective public health response and designed in a way that allows modifications without compromising during the COVID-19 pandemic is the timely communication of the overall integrity and utility of data obtained. test results. This can prevent undue quarantine or ensure people who test positive can be notified in a timely manner and isolated. How will you address cross-cutting issues? This necessitates the transport of clinical samples from collection With partners who will support implementation of your overall surveil- facilities to laboratories, and then of results back to the patients. lance strategy, consider how your approaches will potentially be Scaling testing, while straining transportation networks, may have impacted by each of the following areas: unwanted consequences. • Laboratory infrastructure, capacity, and supply chain. The • Information systems. For data to be useful and actionable, timely addition of new testing and surveillance approaches are likely to put turnaround and analysis of results are necessary. Consider whether pressure on existing laboratory infrastructure, capacity, and supply information systems are robust and have the necessary support in chains. Will certain testing and surveillance approaches require new place: reliable and integrated data collection, laboratory information infrastructure or validation? If so, this is likely to take time to develop. systems, database or data repository for analyses and visualizations, Existing public RT-PCR capacity may be used by clinical testing. and established pathways for dissemination of results. Are approaches amenable to using point-of-care tests without significant loss in utility and impact? Could capacity be leveraged Estimate Costs and Required Resources from the private sector or academic institutions? How will this be The costs and resources required for implementing a accomplished? To maintain testing and surveillance programs, surveillance strategy are some of the most important secure supply chains are essential. Are avenues of purchase, factors that need to be considered. Given the variety of different procurement, and distribution solidified? Consider looking forward surveillance approaches that can be included in a national strategy, to project demand and plan accordingly. it is beyond the scope of this guidebook to give prescriptive guidance • Human resources. Consider the necessary human resources across on potential costs and resources required for all possible surveillance all levels of implementation. Do you have sufficient clinical staff to approaches; however, an underlying principle is that strategies collect specimens? Will these resources be strained during infection should be developed to be sustainable and adaptive to changing waves? Are laboratories sufficiently staffed to analyze specimens in a fiscal constraints. In general, standardized methodology should be timely manner? Based on the data you expect to generate from your used when assessing the costs and resources required for each surveillance approach, do you have the required data managers, surveillance approach, with similar metrics and outcomes to permit analysts, and communicators? If current human resources are comparability. This is particularly important when resources are insufficient, are there pathways to increase capacity—such as task limited and the expected benefits of different approaches are similar. shifting or leveraging the private sector? The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 46 4 2 3 The most tangible costs are those associated with operation—for example, • Multidisciplinary approach. Collecting, analyzing, interpreting, and the cost of collecting, analyzing, and reporting results for a specimen. communicating surveillance data requires a multidisciplinary team These can typically be thought of in three distinct categories: personnel, that works in harmony toward a common goal. Good partnerships materials, and overhead. It is important to also consider start-up costs, between stakeholders involved in all aspects of surveillance are which may include large capital purchases (such as building infrastructure, essential to keep programs running smoothly and efficiently. equipment, and information technology), ongoing costs of implementa- • Data quality benchmarks. With so many different sources of tion and maintenance (such as quality control, monitoring and evaluation, surveillance data, it is imperative to ensure the data collected are and technical support), opportunity costs (such as hidden costs associ- high quality. Pilot studies in more controlled environments can ated with diverting resources from other programs), and costs associated help set data quality benchmarks and permit validation. What will with underuse. Each of these costs will be unique to the country (and even your response be if strange signals are seen? How will irregularities locality) where the surveillance approach is implemented. be investigated and corrected? These data quality assurance In general, costs associated with each surveillance approach can be and improvement procedures should be transparent to build and compared to the costs averted through public health responses that establish trust between stakeholders and the public. result from the information gained through the specific surveillance • Establish a response plan before implementation. Given that there approach you are considering. This may include costs associated with may be multiple avenues of public health response based on testing reduced hospitalizations and intensive care stays, mortality, work absen- and surveillance data, it is critical to establish early on the different teeism, or economic consequences of highly restrictive public health potential responses that could result. Are there already mechanisms measures. Although this is often hard to estimate, one approach could in place to support communication among stakeholders and with be to compare lead time offered by different surveillance approaches to the public? Are there criteria established to trigger different public new waves of infection. Another approach could be comparing time to health measures? identification of emerging variants with currently implemented clinical testing or surveillance approaches. Both approaches can be combined with modeling to estimate potential cost trade-offs. Ensure Results Will Inform Public Health Responses Surveillance programs should be built to be capable of proactively informing the country’s public health response. In developing the overall surveillance strategy, it is important to also prepare for how data will be monitored, analyzed, reported, interpreted, and used. There are several factors to consider: The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 47 Phases of a National Testing and Surveillance Program Phase 3 — Implement Engage stakeholders and optimize your testing and surveillance 1 strategy. Put your new strategy into action. Engage Stakeholders 4 2 Implement Phase 3 When a preliminary strategy has been developed, the next key phase is to broaden the scope of stakeholders 3 engaged as you prepare to fine-tune and implement the strategy. The success of a national testing and surveillance strategy relies on Engage stakeholders leveraging individual and institutional resources throughout all phases of the cycle. The people and agencies (including implementing partners and laboratory, supply, and data teams) that will be involved in putting Pilot and scale the strategy into action are vital partners. Engaging them will help you your program refine the strategy and optimize its implementation, so this process should begin as soon as the general approach has been defined. This will help cultivate ownership and buy-in of the strategy and improve the Strengthen, Adapt, chances of success in every phase of the cycle. Successful strategies Sustain have ongoing cooperation and input from diverse groups of stake- holders, with effective communication on goals and processes to ensure that available resources are used efficiently. Putting your strategy into action involves the following key groups of personnel (figure 14): • Implementing Partners • Laboratory Systems • Data Management • Supply Chain • Health Care Sector The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 48 4 2 3 Figure 14. Key Human Resources to Engage When Implementing Your Strategy • Economic Sectors • Community Groups • Administrative Personnel Testing systems are human resource intensive. They require the diverse groups of individuals with • PAHO different areas of expertise in the right numbers. The scope and scale of human resource needs • Academic or Private Institutions IMPLEMENTING must be actively managed within the context of national strategies. PARTNERS • Offices of National Statistics or Census Persons or groups that can help support buy-in among prioritized populations • Laboratory Representatives • Procurement • Transportation Sector Key sectors that will be involved in implementation LABORATORY SYSTEMS People who will be responsible for data management and analysis and/or familiar with • Data Stewards current surveillance and data management systems • Data Managers • Surveillance Individuals, organizations, or government departments with experience • Epidemiologists coordinating/implementing similar endeavors • Data Analysts DATA • Administrative Personnel MANAGEMENT • Data Communicators People with knowledge of the laboratory infrastructure • Systems Managers • Procurement People with knowledge of human resources available to be leveraged • Transportation Sectors • Distribution SUPPLY • PAHO People with knowledge of supply chain and procurement mechanisms CHAIN • Public Health People involved in current testing strategies with knowledge of data collection, • Epidemiologists transportation, and other tasks • Surveillance • Primary & Community Health Workers People with the skills and means to interpret and disseminate surveillance data clearly HEALTH CARE • Risk Communicators and transparently SECTORS The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 49 Implementation Considerations for Each Group of Personnel to your context. They can offer guidance on best practices for With your engaged group of stakeholders, revisit several preliminary population sampling, potential use cases (that is, when you might considerations on the scope of your testing and surveillance strategy. consider using such approaches), and strategies for testing, and This will ensure that what you seek to accomplish is possible and available technologies. potential issues are identified early. Many considerations are cross- Laboratory Systems cutting among the groups of personnel. The laboratory systems in your country are critical to the success of Implementing Partners any testing and surveillance strategy. Engaging with representatives in the laboratory system will provide insight into procurement schedules, Engaging with implementing partners early is vital to increase the transportation networks, and available capacity. These people will be likelihood that testing and surveillance strategies will be successful. able to provide guidance on what is feasible and potential mechanisms Implementing partners may include people in public or private sectors; to speed up procurement and expand capacity. community organizations; and local, regional, national, and international organizations. These people should have experience in engaging the • Laboratory representatives will have insight into procedures for populations you are prioritizing or in implementing similar strategies and specimen accessioning, analysis, and result dissemination. They can share lessons learned. can help define expected laboratory turnaround times at different volumes of clinical specimens and give realistic estimates of overall • If certain economic sectors are prioritized in the national testing capacity, highlighting what might be feasible and useful moving and surveillance strategy, bring sector representatives to the table forward. They will also be able to provide insight into quality control so that methods and logistics around testing and surveillance can and quality assurance mechanisms that are in place, building confi- be discussed. This should include defining what sector-specific dence in the validity and reliability of results. metrics are most important to them and how the overall success of the program will be measured. • Engaging with personnel involved in procurement of laboratory supplies will allow forecasting of required lab materials, reagents, and personal • Community groups offer extensive experience and insight with protective equipment, minimizing the risk of interruption of testing and population groups that may be prioritized for testing and surveillance. surveillance activities are interrupted due to material shortages. They generally have good insight into existing barriers and facilitators to participation in testing and surveillance activities and mechanisms • Integrated specimen transportation networks—for clinical to address or support these. This also brings the groups impacted specimens arriving from testing facilities or for SARS-CoV-2 by your program to the table, making them part of the process and specimens sent for sequencing—are necessary to ensure the testing supporting buy-in. and surveillance data collected are actionable rather than historical. Delays in specimen transport can significantly impact turnaround • International entities like the WHO or PAHO offer global insight into time and impede appropriate action. Considering how the areas or implementation successes and challenges that may be translatable The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 50 populations targeted for testing and surveillance will be served by With these groups, criteria for action and escalation when unusual transportation networks is essential in this phase. signals are identified can be established. Data Management • Work with data analysts and data communicators to establish processes for how data will be interpreted and communicated to Working with the groups of personnel who will handle and manage stakeholders in a timely, clear, and transparent manner. Set dissem- testing and surveillance data from the time of collection to time of ination schedules and mandatory reporting items that are needed dissemination to stakeholders and the public is essential. Testing and by end users. surveillance are done for specific purposes, and if data gleaned from such endeavors are not suited for purpose, resources are wasted, with Supply Chain high opportunity costs. The COVID-19 pandemic has stressed supply chains globally, in terms of • Engage with end users of testing and surveillance data: surveillance both supply and demand. Current realities—reduced production capaci- managers, epidemiologists, and decision-makers. What do they wish ties, reduced staffing, shortages of raw materials—mean that implemen- to do with the data collected? Work with them to think forward to tation plans may need to be rapidly adjusted to changing landscapes. other potential uses of the data down the line—how can such data Working with all groups involved in the supply chain, including those address future questions? For example, hospital-based surveillance involved in forecasting demand, procurement, and distribution, can permit mechanisms may have a primary aim of monitoring capacity and the development of contingency plans should supply chain issues arise. number of hospitalized COVID-19 patients. However, data from such • Speak with those involved in executing your testing and surveillance mechanisms, if they also capture certain characteristics of hospi- activities to fully understand the types of items they need to success- talized patients, can serve a second purpose—identifying at-risk fully complete their tasks. Whereas laboratory reagents and test kits populations who may benefit from more intensive monitoring or use are important, so too are ancillary items such as test tubes, cleaning of therapeutics. Be aware that this will require careful development materials, and personal protective equipment. Gather information of appropriate data collection systems. Be alert, also, to the volume on whether items have been in limited supply in the past so you can and burden of data collection—too little data may be of little utility, pre-emptively make contingency plans. but a goal of collecting too much information might not be achieved. • Work with local, regional, national, and international organizations • Working with groups of personnel involved in the management responsible for procurement. Understand logistics of ordering of data collection systems—such as data stewards, analysts, and receiving items and alternative pathways of procurement. The and managers—can make clear how information is collected and responsibility for procurement of materials necessary to implement communicated between institutions. Bottlenecks can be identified, a testing and surveillance program at the national level may not lie and systems or approaches can be adapted to ensure key data are only with national organizations. Navigating the procurement system collected and communicated between actors in a timely manner. efficiently is critical for continuity of surveillance programs. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 51 • Distribution of purchased materials often relies on transportation health. In many countries, large infection waves have overwhelmed sectors, and delays between ordering and receipt may vary by region such programs. How to deal with these potential realities should be and locality. Understanding lead-time and distribution barriers early addressed. allows for proactive planning to minimize supply-chain disruptions. • Public health and risk communication is an essential aspect of Health Care Sector effective responses to SARS-CoV-2. Effective, clear, and transparent communication builds trust in the science and the proposed The success of testing and surveillance activities hinges on the approach. Work with people in the health care sector responsible for participation and active involvement of members of the health care communicating between different levels within the sector and with sector. Engagement of both private and public health care workers is the public. Anticipate potential issues and address uncertainties essential. For nearly all forms of testing and surveillance, the people around the proposed testing and surveillance approach early. Clear, being tested or surveyed will interact directly with a member of the health consistent messaging should be a priority. care sector. Clear and transparent communication on how and why different testing and surveillance approaches are being implemented will support uptake by both participants and members of the health care sector. • Discuss implementation of testing and surveillance activities with primary care and community health workers. Ensure the rationale is transparent and the specific procedures are clear. For example, if a specific subgroup of individuals is now to be prioritized over others for PCR testing, the rationale for such a decision should be explained. Consider feedback and concerns, and make sure they are acknowledged and addressed as much as possible. Particularly for active testing and surveillance, primary and community health workers will be front-line implementers and need to trust and believe in the approach. Photo credit: Tim Dennell • Work with public health representatives to ensure the testing and surveillance approach, as well as its timeline, are feasible. Discuss potential issues that may stem from new responsibilities, and develop contingency plans. For example, if contact tracing is to be carried out, responsibility to implement will normally fall on public The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 52 4 2 3 Pilot and Scale Your Program As you roll out your new testing and surveillance program, beginning with pilot projects is a useful way to identify challenges and promote buy-in to the overall program prior to scale-up. During the pilot phase, close collaboration between all actors involved is crucial as they will all be involved with progressive scale-up of the program. As seen in the case example from Slovakia (on the use of population-wide antigen testing), pilot counties were selected prior to country-wide scale-up. Regardless of whether you are implementing tried and tested surveillance methods or innovative approaches, pilot phases are an important step in the implementation pathway: • They help you better understand the potential resource demand upon scale-up, allowing you to refine projections and return to key groups of personnel to adjust implementation plans. • They allow you to estimate the potential yield and added value of different testing and surveillance approaches. When resources are limited, not all testing and surveillance approaches can be used. Implementing several different approaches as pilots can help elucidate which approaches should be brought forward for country- wide scale-up, and which could be abandoned. • They allow you to identify logistical challenges across the entire Photo credit: Roberto Jorge Freire Esteves/CDC implementation pathway. The success of programs relies on all actors and processes working seamlessly, and pilot phases are useful in identifying and addressing difficulties—ranging from simple misalignment of required data points between health facilities and national surveillance units, to more fundamental issues related to capacity and supply chain or collaboration between required actors. The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 53 4 2 3 Strengthen, Adapt, Sustain Vietnam. This dropped analysis time to a little over an hour, with costs as Strategies within your overall testing and surveillance low as US$20 per test (Klingler-Vidra, Tran, and Uusikyla 2021). Adapting program are likely to have different aims, applications, testing protocols to use these test kits would thus save time and money, and sampling characteristics. When a new strategy (or strategies) changing the cost-benefit calculus of testing and surveillance strategies. is implemented, there is a period of adaptation and learning—such Similar innovations are occurring globally. as learning how best to implement specimen collection, specimen Future Applications transport, and information systems, or understanding which populations may benefit from different strategies, what barriers Experience with testing and surveillance strategies has potential exist, and how data generated compare to existing methods. When benefits beyond the COVID-19 pandemic. For example, strengthening new strategies are implemented, collaborations between different of information systems to permit robust testing and surveillance not stakeholders are likely to be formed. Taken together, this amounts only will pay dividends for other existing health threats, but will make to a period of strengthening, where your program should see quick health systems better prepared to detect and react to the next public efficiency gains and improved understanding of new data collected health threat. Similarly, development of laboratory PCR capacity can be from your testing and surveillance program. leveraged for testing of other pathogens, such as tuberculosis. Experience with deploying population self-testing with rapid tests can similarly be Adapting to Innovation leveraged for at-home testing of pathogens like human immunodeficiency Collaboration between different sectors and with the international virus (HIV). Finally, beyond obvious technological and process benefits community provides researchers with the know-how and resources associated with implementing a testing and surveillance program, health to innovate. As more tools become available, it is key to consider how and human resource capacity will be bolstered, collaborations with they might be used, as this can have important impacts on cost-benefit different stakeholders will be forged, and public health infrastructure will calculation or address existing barriers. be developed, increasing health system resiliency. Contextualizing innovation is as essential as having resources and knowledge. An example of this can be seen in Vietnam. Even before the first case of COVID-19 was reported in Vietnam, the private and public sector worked together to develop PCR test kits that were more affordable and could be completed more rapidly than existing options. They worked to understand how these new kits could be validated and implemented in their context. They realized that the preliminary, time-consuming steps in more widely available test kits (such as those provided by the WHO and US-CDC) were unnecessary based on coronavirus epidemiology in The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 54 Phases of a National Testing and Surveillance Program 1 Phase 4 — Evaluate Evaluate your overall surveillance approach, adapt it, and renew the cycle 4 2 Evaluate Phase 4 The implemented surveillance approach needs to be critically and comprehensively evaluated to understand its successes and challenges 3 and, if necessary, to adapt or refine the strategy. An evaluation should Purpose of the look carefully at whether strategies are reaching their goals. Consider the program development and implementation of an overall surveillance strategy as an iterative process, cycling again through the four phases used to initiate and integrate new approaches into your testing and surveillance program. Utility of the data A careful evaluation will prepare you to improve your overall surveillance strategy and be ready to adapt it to the rapidly changing pandemic land- scape and your local context. Established recommendations for evalu- ating surveillance systems build on seven key areas: Costs and acceptability • Purpose of the program • Utility of the data Feasibility, flexibility, • Costs and acceptability and sustainability • Feasibility, flexibility, and sustainability • Barriers and facilitators • Equity and ethical issues Barriers and facilitators • Potential adaptations for next cycle Purpose of the Program Equity and You have implemented a testing and surveillance program ethical issues and collected data for a specific purpose—primarily, to proactively inform public health measures and better understand the extent and dynamics of SARS-CoV-2 infection. However, your program Potential adaptations for may serve several other purposes, such as to establish baseline A B the next cycle epidemiologic data as a foundation for future monitoring and research, The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 55 4 2 3 or to be sensitive to specific signals in certain populations. Once your • Reliability. Were the data operational when needed? Were there testing and surveillance program is in place, revisit the purpose and the data issues during collection, analysis, or dissemination? objectives of the program. Consider whether the program is providing • Standards use. Were appropriate protocols followed when you the information you require to reach its goals, whether the program collecting, managing, and analyzing the data? Did the technologies is efficient and performing as you envisioned, and whether the context follow approved algorithms or use cases (that is, appropriate recom- has changed and adjustments might be required. mendation of PCR testing, use of rapid antigen tests, or referral of positive specimens for sequencing)? Utility of the Data Data evaluation begins right after data have been collected • Availability. Were testing and surveillance data available to all and analyzed. If the data collected from your testing and stakeholders and provided/presented in a transparent manner? surveillance program did not prove useful for its intended purpose (for Were data publicly available? Were data held in a confidential and example, informing public health measures), review the possible expla- private manner when required? Were potentially identifiable data nations. Solutions should be examined in the context of other consid- handled appropriately? erations, including added costs and any impacts on acceptability and • Timeliness. Were testing and surveillance data analyzed and feasibility. Consider both strengths and weaknesses in the collected disseminated in a timely manner for public health decision-makers data. It is likely the cost-benefit calculus you estimated for your testing and other end users? Were there time delays between steps in the and surveillance program may now be different and come with important surveillance process? opportunity costs. Identify whether issues in data utility are possible to address, and attempt to arrive at solutions. Costs and Acceptability To help your evaluation of data utility, consider the following areas: Testing and surveillance programs are designed to fit within specific budgets and serve specific purposes. • Data quality. Did the testing and surveillance program provide the Anticipated costs before implementation should be reviewed against required data? Were quality assurance and control methods applied? the actual realized costs after implementation. This review should inves- Are the data complete and valid? tigate areas where realized costs were higher or lower than anticipated • Efficiency. Was the implementation of the testing and surveillance and consider why costs deviated. program an efficient use of resources (financial, human, lab, and so • Are there areas where costs could be saved moving forward? forth)? What barriers need to be overcome? Economies of scale should be considered. • Sensitivity, specificity, and positive predictive value. Did the • Where were excess expenditures most common in terms of testing and surveillance program do what you intended—for types of cost (such as personnel, materials) and when they were example, did it accurately identify new outbreaks, surges, and waves, incurred (such as during coordination, sampling, transport, or yield data useful to target vaccination and booster programs? analysis, communication)? The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 1 56 4 2 3 These evaluations are key to ensure cost-benefit calculations regarding • What was the financial, human resource, and lab capacity strain the implemented strategy hold, moving forward, and to inform the imposed by the testing and surveillance program? Can it be main- development of other strategies and improve implementation efficiency. tained? What changes could support sustainability? Take careful stock of the opportunity costs of your program in terms of • What was the overall cost of the program, and how does this relate human, laboratory, and other community resources required for efficient to existing budgets? Even cost-effective programs may burn through and effective implementation. existing cash flow and become infeasible. • Was implementation of the testing strategy an efficient use of • What materials and supplies were required? If reliable procurement resources? is not possible, strategies will be unsustainable. • Can efficiency be improved? Are new technologies available to increase this efficiency? Barriers and Facilitators Consider barriers that had to be overcome and which Uptake of the strategy by all participants (the people being tested or factors supported implementation of your testing and surveyed) is paramount to its effectiveness and utility. Throughout surveillance program. Qualitative assessments to understand barriers implementation it is necessary to maintain indicators of acceptance and facilitators are vital components of quality improvement frameworks. (for example, adherence to protocols, participation in surveillance Such assessments engage the personnel involved in implementing the programs). Reasons for suboptimal uptake should be explored. Factors strategy, as well as program participants, to learn what helped them carry vary and may include those associated with convenience, test-specific out their tasks, what got in the way, and what would make a difference characteristics, logistics, or buy-in from the population. Future strategies in the future. Combine such qualitative assessments with quantitative will benefit from this evaluation to ensure more participant-centered assessments of certain program indicators—such as lab turnaround approaches are employed. time and population coverage—to better understand barriers and • Was there sufficient uptake and was the strategy acceptable to facilitators. This process is iterative, with constant evaluation. both the people participating in testing and surveillance and the Open or structured discussion with personnel and with program personnel involved in implementation? participants is a useful method to elicit information about what helped or Feasibility, Flexibility, and Sustainability hindered success. Often, respondents provide useful insights and offer possible solutions to commonly encountered barriers. Results from When examining whether your overall testing and the qualitative assessments should be used to support and reinforce surveillance program or a specific approach should be facilitators and attempt to remove or mitigate potential barriers to repeated and/or continued, it is important to consider how feasible and improve efficiency in delivery. sustainable it is and how flexible each approach can be moving forward. Consider: The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 57 Equity and Ethical Issues the personnel needed. New iterations of immune assays or antigen tests Different populations may be engaged with different may have key changes in performance (that is, sensitivity and specificity) testing and surveillance approaches within your overall that require careful reassessment of use cases. Likewise, the number of program. A major goal of comprehensive testing and surveillance people reached within strategies may change with innovations. programs is to have a complete view of the population, with specific Testing and surveillance strategies cannot remain stagnant and need to approaches used to reach underrepresented populations and address be responsive to innovations. Therefore, they must be constantly evalu- inequities. Was your program successful in this regard? If not, why? ated. You should review your current practices against the best practices Consider: worldwide. Consider innovations that can shift the accuracy, cost, and efficiency of testing and surveillance approaches. Your evaluation should • Were certain population groups missed by your program? What was help you prepare to adapt the next iteration of the strategy to benefit the population coverage? from new methods, technologies, or other innovations. • Were the included populations representative of the entire popula- tion? Can findings be readily generalized? The Process Is Cyclical • Was equity achieved? Did your program consider key groups that In the context of a continuing, changing pandemic, a repetitive strategic are at increased risk of infection or severe outcomes or that are cycle is vital to ensure efficient delivery of scarce resources, maximize typically under-represented (such as those in informal settlements population health, and mitigate the social and economic impacts of or congregate settings)? COVID-19. • Did any ethical issues arise? Did anyone or any group experience An iterative process—of assessing your resources, renewing or harm from the testing and surveillance program? redesigning a strategy around identified priorities, engaging with key players to give your implementation the best chance of success, and Potential Adaptations for the Next Cycle re-evaluating the processes and outcomes—will help your surveillance Testing and surveillance strategies are rapidly evolving, A B approaches respond to new conditions and new opportunities. and so too is the pandemic context. Not only is the tech- First iteration: When a thorough evaluation has been performed, the nology we use changing, but also who can be leveraged to perform tests process of prioritizing populations, developing and optimizing a strategy, (trained personnel, the subject through self-testing), where tests are and implementing the strategy repeats. analyzed (for example, laboratories, within the home), and the types of surveillance needed (for factors such as variants of concern, waning Subsequent iterations: This process can be expedited in comparison to population immunity, vaccine coverage, mental health). Innovations the first iteration, using the experience and knowledge gained, but the and changing needs have implications for the cost-effectiveness of process should not be omitted. Priorities shift and so, too, do available testing and surveillance programs, the testing capacity required, and resources. What is needed now? What is realistic? The Value of National Toward a Proactive Testing and Surveillance The Strategy Toolbox Approach to National Strategies Testing and Surveillance 58 First iteration It is not always possible to implement and evaluate a national testing and surveillance strategy in tidy, distinct phases. Speed trumps perfection in public health emergency response. Whereas the first iteration may be quickly put together, subsequent iterations offer an opportunity to improve 1 and apply lessons learned. As the world grapples with emerging variants of concern and vaccine inequity, it is clear that testing and surveillance will remain essential for the public health response to SARS-CoV-2 for the foreseeable future. Endeavoring to create a well-designed, adaptive, Assess existing surveillance approaches and integrated approach to testing and surveillance that provides data for and available resources proactive action today will pay dividends in the future. Consider: What do you currently know? 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