WASHINGTON, United States — Wastewater testing, according to a new World Bank report, provides a relatively economic method whereby countries in Latin America and the Caribbean can improve their detection, diagnosis, control, and monitoring systems for viruses that cause diseases like COVID-19 and its variants.

This tool, which complements clinical studies, allows public policymakers to have a comprehensive, sustainable, early warning, and equitable tool to improve public health responses.

Latin America and the Caribbean is one of the epicentres of the pandemic, with some of the highest mortality rates in the world and more than 1.56 million deaths. With its unrelenting social and economic consequences, COVID-19 threatens to undo recent gains in human capital outcomes in the region.

In this context, wastewater testing can, at a relatively low cost, provide information on the circulation of the virus and identify clusters of cases before the situation reaches the level of sustained transmission. This early warning allows public health professionals to detect potential outbreaks and quickly implement targeted control measures.

The new report, Strengthening public health surveillance through wastewater testing — an essential investment for the COVID-19 pandemic and future health threats, highlights that wastewater testing can facilitate the collection of useful information about vulnerable populations or groups in remote locations, especially those who do not have access to clinical tests for COVID-19. The collection and testing of samples in certain at-risk settings provide reliable information and can therefore prevent outbreaks that could overwhelm the local health-care system, especially with the emergence of new worrying variants such as Omicron.

Carlos Felipe Jaramillo, World Bank vice-president for the Latin America and Caribbean region, said “The [novel coronavirus] pandemic has meant the loss of years of development gains for many countries in the region, and has highlighted the need to develop new tools to better prepare for and respond to future crises. The region can benefit from using its water and sanitation infrastructure for public health risk surveillance, such as COVID-19. The World Bank will help countries finance and implement this type of smart investment to help solve their complex problems.”

The report further states that investments in wastewater monitoring systems can yield long-term benefits to strengthen countries’ capacity to provide timely and well-informed public health responses.

Leaders around the world, including those in Latin America and the Caribbean, still have many opportunities to implement wastewater surveillance to help combat COVID-19. Most low-income countries have not yet begun to conduct tests, despite the general agreement that these countries are the ones that will benefit most from these types of trials, given their low-resource requirements in comparison to other surveillance approaches.

Beyond the current crisis created by the pandemic, wastewater testing can give a snapshot of the health of communities upon analysis of a variety of pathogens present in wastewater. Its use facilitates timely and more comprehensive public health responses to diseases like hepatitis A, influenza, and other community health risks such as antimicrobial resistance, chemical drug abuse, or overuse of pesticides.

Best practices therefore need to be developed for measurement and the generation of reports, as well as to enable collaboration and coordination between health entities, laboratories, and services that are involved in wastewater collection. This will require infrastructure that allows for a broader, well-organised, and sustainable surveillance system.