Effectiveness, Feasibility and Seasonality of Subsewershed Disease Surveillance in Socially and Economically Diverse Areas of Cincinnati, Ohio, in 2023 and 2024; Insights from Laboratory and Rapid Testing Analysis

Wastewater surveillance gained popularity as a tool supporting public health decision-making during the COVID-19 pandemic. In this study, we monitored four distinct socially vulnerable communities in Cincinnati, Ohio, by monitoring four subsewersheds using 15 upstream locations over two time periods: spring/summer (2023) and fall/winter (2023–2024). The goal of our study was to evaluate the feasibility and effectiveness of monitoring wastewater in socially and economically diverse subsewersheds. A number of 24 h composite samples were collected twice a week and analyzed for SARS-CoV-2 viral loads in the four subsewersheds and two wastewater treatment plants (WWTPs). Wastewater quality parameters (electric conductivity, pH, temperature, ORP) were also measured continuously. During the fall/winter period, increased clinical cases were correlated with high SARS-CoV-2 viral concentrations indicated by both subsewershed and WWTP monitoring. In our study, subsewershed monitoring did not provide early warning of SARS-CoV-2 levels in wastewater and cases compared to WWTP wastewater monitoring during the fall/winter period when outbreaks with higher pathogen levels often occur. This was possibly due to the proximity of the selected subsewersheds to the WWTPs. Although two socially vulnerable subsewersheds had higher SARS-CoV-2 viral concentrations in wastewater, the most vulnerable subsewershed had the lowest wastewater concentrations and the lowest number of reported cases during our study. Therefore, social vulnerability is not always the best predictor of the community COVID-19 burden since other factors may play a role in community infection, including transiency and population age distribution. This study presents some challenges and important findings from subsewershed SARS-CoV-2 wastewater monitoring during two seasons in Ohio.