Efficacy of SARS-CoV-2 wastewater surveillance for detection of COVID-19 at a residential private college

Abstract

AbstractMany colleges and universities utilized wastewater surveillance testing for SARS-CoV-2 RNA as a tool to help monitor and mitigate the COVID-19 pandemic on campuses across the United States during the 2020-2021 academic year. We sought to assess the efficacy of one such program by analyzing wastewater RNA load data in relation to SARS-CoV-2 cases identified through individual surveillance testing. Almost 80% of the cases on campus were associated with positive wastewater tests, resulting in an overall positive predictive value of ∼79% (Chi square 48.1, Df = 1, p < 0.001). However, half of the positive wastewater samples occurred in the two weeks following the return of a student to the residence hall following isolation, and therefore were not useful in predicting new infections. When these samples were excluded, the positive predictive value of a positive wastewater sample was ∼54%. Overall, we conclude that the continued shedding of viral RNA by patients past the time of potential transmission confounds the identification of new cases using wastewater surveillance, and decreases its effectiveness in managing SARS-CoV-2 infections on a residential college campus.