More than a Tripledemic: Influenza A Virus, Respiratory Syncytial Virus, SARS-CoV-2, and Human Metapneumovirus in Wastewater during Winter 2022-2023

Wastewater monitoring can provide insights into respiratorydiseaseoccurrence in communities that contribute to the wastewater system.Using daily measurements of RNA of influenza A (IAV), respiratorysyncytial virus (RSV), and human metapneumovirus (HMPV), as well asSARS-CoV-2 in wastewater solids from eight publicly owned treatmentworks in the Greater San Francisco Bay Area of California betweenJuly 2022 and early July 2023, we identify a "tripledemic"when concentrations of IAV, RSV, and SARS-CoV-2 peaked at approximatelythe same time. HMPV was also widely circulating. We designed novelhydrolysis probe RT-PCR assays for different IAV subtype markers todiscern that the dominant circulating IAV subtype was H3N2. We showthat wastewater data can be used to identify the onset and offsetof wastewater disease occurrence events. This information can provideinsight into disease epidemiology and timely, localized informationto inform hospital staffing and clinical decision making to respondto circulating viruses. Whereas RSV and IAV wastewater events weremostly regionally coherent, HMPV events displayed localized occurrencepatterns.