Better testing and surveillance are essential for resilient health systems

The Latin America and Caribbean (LAC) region was not spared of the omicron variant, detected in November 2021 in South Africa and classified as a variant of concern. Countries around the world were called upon to enhance not only surveillance activities but also sequencing efforts. Even those with more robust testing systems in LAC, such as Uruguay, were quickly overwhelmed. At the start of December 2021, the country was testing 43 people per case detected; by February 2022, this number had fallen to less than 3.

Though globally COVID-19 cases have fallen from their peak in early 2022, omicron continues to circulate with five omicron subvariants being actively monitored as of December 2022. Cases are beginning to precipitously rise as 2023 commences.

The effects of the pandemic and ongoing global crises, such as the war in Ukraine and surging inflation, have been hard and profound. Though most of the 7 percent Growth Domestic Product (GDP) contraction experienced in LAC in 2020 due to the pandemic was mostly recovered in 2021, GDP growth in 2022 and projected growths in 2023 and 2024 are much more modest. A surge in COVID-19 infections could threaten economic growth in the region once again. 

Testing and population-level surveillance activities are an underappreciated but vital component of national strategic plans to prevent and respond to SARS-CoV-2 and other public health threats , to protect human capital and economic activity. As part of a national strategy, testing and surveillance activities bring indispensable value to a country’s public health response, providing data and evidence that can support proactive rather than reactive measures. But what does this mean and how does it work?

In practice, it means leveraging both passive and active forms of testing and surveillance to inform resource allocation, understand transmission dynamics, support vaccine and genomic surveillance, and monitor population immunity.

Passive and active surveillance activities

Incorporating these activities into national strategic plans is the key message of a guide developed by the World Bank containing practical knowledge to help governments monitor SARS-CoV-2 and population immunity, stay ahead of subsequent pandemic waves, prioritize populations for vaccination and protective measures, and decide on proactive public health measures to mitigate the impacts of the pandemic in different communities.

Passive surveillance activities do not typically require substantial new or ongoing investment, and make use of existing systems, samples, and/or data. The guide covers:

• Syndromic surveillance
• Serosurveillance
• Wastewater-based surveillance
• Hospital-based surveillance
• Mortality-based surveillance
• Genomic surveillance

Active surveillance activities are more purposeful and generally require investment and effort to implement, but the data gathered are less prone to bias and support more proactive, data-driven tailoring of responses. The guide covers:

• Contact tracing and testing
• Serial testing in high-risk settings
• Targeted testing and surveillance
• Representative population or sentinel surveys
• Prospective epidemiologic studies

Implementing a Proactive Approach to Surveillance

The World Bank guide for effective national testing and surveillance strategies for COVID-19 in LAC provides practical advice based on best available international experience for countries to develop proactive strategies  that will help them respond to COVID-19 and future public health threats.

The guide covers essential elements for governments to consider as they develop and implement their proactive testing and surveillance strategies:

• Availability of data, resources, and health human resources including the range and quantity available and required for potential strategies
• Importance of good governance, use of best available data, and stakeholders’ engagement to define priority testing and surveillance activities to be implemented and the populations to be targeted
• Key implementation considerations required for successful implementation such as laboratories infrastructure and capacity; reliability of supply chains; transportation networks; human resources; and surveillance infrastructure and data communication
• Importance of continuous evaluation and learning to refine strategies as they are implemented

Financing and implementing proactive, population-based surveillance strategies will be essential to strengthen the resilience of health systems in Latin America and the Caribbean , as proposed in a recent World Bank publication.

Ultimately, surveillance is but one important link in the detection and response chain to public health threats. But as we have seen with Ebola and mpox in 2022, these threats can occur anywhere at anytime. Developing infrastructure and implementing surveillance activities at the population level can support the continued response to public health emergencies, strengthen the resilience of health systems, and help protect human capital and the economy.