COVID-19 in Connecticut institutions of higher education during the 2020-2021 academic year

Schultes, O.; Clarke, V.; Paltiel, A. D.; Cartter, M.; Sosa, L.; Crawford, F. W.

Background: During the 2020-2021 academic year, many institutions of higher education reopened to residential students while pursuing strategies to mitigate the risk of SARS-CoV-2 transmission on campus. Reopening guidance emphasized PCR or antigen testing for residential students and social distancing measures to reduce the frequency of close interpersonal contact. Connecticut colleges and universities employed a variety of approaches to reopening campuses to residential students. Methods: We used data on testing, cases, and social contact in 18 residential college and university campuses in Connecticut to characterize institutional reopening strategies and COVID-19 outcomes. We compared institutions' fall 2020 COVID-19 plans, submitted to the Connecticut Department of Public Health, and analyzed contact rates and COVID-19 outcomes throughout the academic year. Results: In census block groups containing residence halls, fall student move-in resulted in a 475% (95% CI 373%-606%) increase in average contact, and spring move-in resulted in a 561% (441%-713%) increase in average contact. The relationship between test frequency and case rate per residential student was complex: institutions that tested students infrequently detected few cases but failed to blunt transmission, while institutions that tested students more frequently detected more cases and prevented further spread. In fall 2020, each additional test per student per week was associated with a reduction of 0.0014 cases per student per week (95% CI: -0.0028, -0.000012). Residential student case rates were associated with higher case rates in the town where the school was located, but it is not possible to determine whether on-campus infections were transmitted to the broader community or vice versa. Conclusions: Campus outbreaks among residential students might be avoided or mitigated by frequent testing, social distancing, and mandatory vaccination. Vaccination rates among residential students and surrounding communities may determine the necessary scale of residential testing programs and social distancing measures during the 2021-2022 academic year.