Norovirus GII wastewater monitoring for epidemiological surveillance

Norovirus surveillance using case reports and syndromic detection often lags rather than leads outbreaks. To assess the timeliness of norovirus wastewater testing compared with syndromic, outbreak and search term trend data for norovirus, we quantified norovirus GII in composite influent samples from 5 wastewater treatment plants (WWTPs) using reverse transcription-digital droplet PCR and correlated wastewater levels to syndromic, outbreak, and search term trend data. Wastewater HuNoV RNA levels were comparable across all WWTPs after fecal content normalization. Norovirus wastewater values typically coincided with or led syndromic, outbreak, and search term trend data. The best correlations were observed when the wastewater sewershed population had high overlap with the population included by other monitoring methods. The provision of norovirus-specific measures and earlier detection of norovirus found using wastewater surveillance suggests that wastewater-based surveillance of human norovirus GII will enhance existing public health surveillance efforts of norovirus. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported by funding from the University of Michigan through the Public Health Infection Prevention and Response Advisory Committee (PHIPRAC), and from the Michigan Department of Health & Human Services through the Michigan Sequencing Academic Partnership for Public Health Innovation and Response (MI-SAPPHIRE) grant (S MA-2022, BF mPI) and wastewater surveillance program (SEWER network grant, KW and ME co-PIs). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The IRB of the University of Michigan at Ann Arbor waived ethical approval of this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work is either contained in the manuscript or available upon reasonable request to the authors.