Impacts of Testing, Vaccination, and Immunity on COVID-19 Cases in Massachusetts Elementary and Secondary Students: A Retrospective, State-Wide Cohort Study

Test-to-stay modified quarantine programs implemented in elementary and secondary schools increased participation in in-person learning during the Covid-19 pandemic . Little is known about the impact of other types of testing programs, such as surveillance testing, or immunity and vaccination, on cases of COVID-19 in elementary and secondary school settings. This retrospective cohort study, which was conducted in the state of Massachusetts during the 2021- 22 academic year, found that high vaccination uptake and community immunity acquired via prior infection mitigated COVID-19 cases in elementary and secondary schools. Testing strategies, including surveillance testing programs and test-to-stay modified quarantine programs, for supporting in-person learning were safe and effective but feasibility challenges are important considerations. These data can be used to inform policy about in-school mitigation measures during future respiratory virus pandemics.