Improving Epidemic Surveillance with Wastewater Analysis: A Cost-Benefit Study
The COVID-19 pandemic has caused adverse effects worldwide, prompting a search for effective methods to track and manage the causative virus. During the pandemic, clinical PCR and antigen tests were primarily used for screening new cases. However, such clinical tests often have limitations, such as missing asymptomatic individuals, struggling to meet demand during outbreaks, facing resistance, and being costly for large populations. Wastewater surveillance can overcome these limitations. Samples from a treatment plant or sewer can represent large populations in neighborhoods or cities.
To explore the potential of wastewater surveillance in disease screening, Professor Byung-Kwang Yoo and his team at Waseda University conducted a model-based cost-benefit analysis. They assessed two hypothetical disease screening approaches for a single residential facility in Japan.
They estimated the return on investment (ROI) for hypothetical screening approaches: option 1 involved using clinical PCR tests to confirm COVID-19 cases following positive antigen test results, while option 2 employed wastewater surveillance as the primary screening method. They tested these screening options for three base-case disease incidence values: 10, 100, and 1000 newly reported clinically positive cases per million residents per day (PMPD) around the selected facility.
The research team measured the ROI of both options compared to doing nothing and compared to each other, wherein an ROI greater than 1 is considered They found that when disease incidence was 10 PMPD and 100 PMPD, neither option 1 nor option 2 were economically viable due to their costs outweighing their benefits, resulting in respective ROIs of less than 1. However, for both these incidence values, option 2 was relatively more economically viable compared to option 1, with a relative ROI of 54 and 6.25 for 10 PMPD and 100 PMPD, respectively. In contrast, for 1000 PMPD, both options alone had an ROI greater than 2 but option 2 had a relative ROI less than option 1.
This indicates that option 2 was more economically viable than option 1 only at incidence levels below 630 PMPD. Further analyses by the team also showed that across 1,000 iterations option 2 was preferred 84.7%, 80.8%, and 25.2% of the time at incidence values of 10, 100, and 1,000 PMPD, respectively. The team also found that options 1 and 2 alone were economically feasible only when the incidence was greater than 480 PMPD and 450 PMPD, respectively. Similarly, both options had fixed break-even points, which included maximum allowable implementation costs and minimum number of residents that justified the use of these options.
Overall, these findings provide evidence to economically justify and promote the use of wastewater surveillance as a primary disease screening option along with clinical tests, both in Japan and globally. They could also have policy implications for routine wastewater surveillance that could help trigger the start of screening tests in high-risk residential areas. Moreover, they could facilitate coordinated implementation of neighborhood- and city-level wastewater surveillance to enhance economic efficiency in disease detection and prevention efforts.
Link to the original journal article: https://wwwnc.cdc.gov/eid/article/29/8/22-1775_article
About the author:
Professor Byung-Kwang Yoo is a tenure-track professor at the Faculty of Human Sciences, School of Human Sciences, Waseda University, Japan. Throughout his academic career, Prof. Yoo has been committed to exploring the significance of preventive health care and its implications for promoting public health and well-being. His research interests include various aspects of health evaluation science and the theory and practice of health education.
