What is this article about?

This article discusses the use of wastewater and environmental surveillance (WES) as a complementary tool to clinical surveillance in South Africa. Historically, WES has been used for monitoring diseases such as polio, and since the COVID-19 pandemic, it has been applied to track new waves of SARS-CoV-2 infections and to monitor the emergence of viral variants.

Why is this issue important?

The importance of WES lies in its ability to detect infections early, as people shed pathogens before symptoms appear. Moreover, in situations where access to healthcare is limited or individuals are hesitant to seek medical attention, WES enables population-level monitoring of infectious diseases. In addition, it is a potentially cost-effective, scalable, and non-invasive surveillance method that can complement traditional clinical systems.

What drew your interest to this area of study?

At the Centre for Vaccines and Immunology of the National Institute for Communicable Diseases (NICD), we serve as the World Health Organization (WHO) Regional Reference Laboratory for polio surveillance and have long been testing wastewater samples for poliovirus, in accordance with WHO standards. During the COVID-19 pandemic, we became interested in determining whether SARS-CoV-2 could also be detected in wastewater, as emerging evidence suggested that the virus is shed in the stool of infected individuals. After successfully implementing WES for SARS-CoV-2, we expanded the scope of this work to include other vaccine-preventable and infectious diseases. We believe that this new surveillance tool will complement traditional, clinically based surveillance systems at the NICD and across South Africa.

What was your role in the research?

I am the Co-Director of the Wastewater Genomics Syndicate at the NICD and a co-founder of the unit. I develop research questions, supervise the team, interpret wastewater surveillance data for multiple infectious diseases, and, as a public health expert, translate findings for decision-makers to inform public health action in South Africa.

Why should people read this article?

As WES emerges as a new public health tool, it is important for people to understand what these community-collected samples can reveal and how they help us monitor the population-level epidemiology of diseases. WES can also provide an early warning mechanism for future outbreaks, strengthening public health systems and improving preparedness.

What impact do you hope the article will have on public health policy and healthcare access?

We hope this article will increase awareness of the value of WES and how it can complement traditional surveillance systems. We aim for public health officials to recognise its utility and integrate it into public health practice. For the public, we hope it demonstrates the strength and readiness of our public health system in preparing for and responding to future outbreaks.

Dr Kerrigan McCarthy is a Principal Pathologist at the Centre for Vaccines and Immunology, the Co-Director of the Wastewater Genomics Syndicate at the National Institute for Communicable Diseases, and a lecturer in the School of Pathology at the University of the Witwatersrand.

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