Identification of Statewide Hotspots for Respiratory Disease Targets Using Wastewater Monitoring Data

As wastewater monitoring networks continue to expand the monitoring of various targets, it is important to ensure these networks remain both representative of their monitored populations and flexible enough to accurately predict shifts in an expanding list of targets. In this study, we analyzed the levels of SARS-CoV-2, influenza A (InfA), and influenza B (InfB) detected in untreated wastewater during the 2023-2024 respiratory season at 70 locations participating in the Ohio Wastewater Monitoring Network. Locations with the first detection that are seasonal hotspots and sites reaching peak concentration for each target were compared and analyzed for dependence on healthcare access and population characteristics, such as population size and density, county traffic, and demographic and socioeconomic factors. The trends in these three respiratory viruses were found to closely mirror trends in clinical indicators including the number of cases and positive tests with wastewater levels providing a two-week lead for SARS-CoV-2 and no lead for influenza on these clinical indicators. InfA was first detected in more affluent sewersheds that were less racially and ethnically diverse and had higher traffic counts, while none of the parameters tested had an effect on InfB first detects. The seasonal hotspots varied for all three respiratory viruses, where InfA hotspots were exclusively in the northeast, InfB was in the southeast and east border areas, and SARS-CoV-2 wastewater hotspots concentrated around central and northwestern Ohio. While wastewater monitoring networks may not offer full coverage of all populous areas, we have shown that a spatially distributed and highly diverse network is needed for early detection of various respiratory targets.