Weekly SARS-CoV-2 screening of asymptomatic students and staff to guide and evaluate strategies for safer in-person learning

Doron, S.; Ingalls, R.; Beauchamp, A.; Boehm, J.; Boucher, H.; Chow, L.; Corridan, L.; Goehringer, C.; Golenbock, D.; Larsen, L.; Lussier, D.; Testa, M.; Ciaranello, A. L.

Background: Data suggest that COVID-19 transmission in K-12 schools is uncommon, but few studies have confirmed this using widespread screening of asymptomatic individuals. Objective: To evaluate the incidence of asymptomatic COVID-19, document the frequency of in-school transmission, and confirm feasibility of widespread asymptomatic screening in schools. Design: Prospective observational study Setting: Single mid-sized suburban school district including 10 schools and a central office. Participants: District staff and students Interventions: Asymptomatic screening PCR for SARS-CoV-2 Measurements: Concurrent with a hybrid model and layered mitigation, weekly pooled testing of staff and secondary students was offered using saliva samples collected at home. Identification of >1 case in a school prompted investigation for possible in-school transmission. Staff and families were surveyed about satisfaction with the screening program. Results: From weeks 1-18, rates of incident COVID-19 in the surrounding community rose steadily. Weekly staff and student screening identified 0-7 asymptomatic cases/week. In week 7, 5 cases were identified among staff who shared an office setting. Enhancements to mitigation strategies were undertaken. The proportion of survey respondents self-reporting comfort with in-person learning before versus after implementation of screening increased. Limitations: Because screening testing was not mandatory, the results from the participating population might not represent the entire school community. Conclusions: In this school district with layered mitigation measures, in-school transmission was rare. The program identified a cluster with in-school staff-to-staff transmission and spurred enhancement of safety strategies. A weekly COVID-19 screening program can provide critical data to inform mitigation efforts, and provides school-specific, current data to inform decisions about in-person learning models. Screening provided reassurance and identified asymptomatic cases. Funding: The Wellesley Education Foundation provided funding for the testing.