Beyond Campus Borders: Wastewater Surveillance Sheds Light on University COVID-19 Interventions and their Community Impact

The evaluation of COVID-19 policy effectiveness on university campuses, particularly in mitigating spread to neighboring cities (i.e., "campus spill-over"), is challenging due to asymptomatic transmission, biases in case reporting, and spatial case reporting limitations. Wastewater surveillance offers a less biased and more spatially precise alternative to conventional clinical surveillance, thus providing reliable data for university COVID-19 policy evaluation. Wastewater surveillance data spanning the academic terms from Fall 2020 through Spring 2022 was used to evaluate the impact of university COVID-19 policies. During the campus closure to external visitors, campus viral concentrations and variant compositions were dissimilar from those of the host and neighboring cities (MAPE = 0.25 + 0.14; Bray-Curtis = 0.68 + 0.1, respectively), indicating relative isolation of the campus from its surroundings. Upon the campus reopening to visitors, the viral concentrations and variant compositions matched more closely with the host and neighboring cities (MAPE = 0.21 + 0.1; Bray-Curtis = 0.14 + 0.08, respectively). Furthermore, post-lifting of campus and state mask mandates, the campus, host and neighboring city viral concentrations and variant compositions became indistinguishable (MAPE = 0.06 + 0.02; Bray-Curtis = 0.07 + 0.05, respectively). This data suggests that university COVID-19 policies effectively prevented campus-spill over, with no significant contribution to COVID-19 spread into the surrounding communities. Conversely, it was the surrounding communities that led to the spread of COVID-19 onto the campus. Therefore, wastewater surveillance proves instrumental in monitoring COVID-19 trends in surrounding areas, aiding in predicting the impact of easing campus restrictions on campus health.