Determining the right mix of COVID-19 mitigation strategies to keep kids safe

As the COVID-19 vaccine has become available to more age groups, the question of whether mitigation strategies should still be used is a topic of hot debate, particularly in schools. A study of a decision analytic model examines when mitigation strategies can be added or removed to ensure the relative safety of students in elementary schools, where a number of students remain ineligible for vaccination.¹

The model simulated the transmission of COVID-19 within a school community and a simulated population of students, teachers and staff, and their household members. The population of the school was roughly the average size of an elementary school in the United States and had including 638 students and 60 educators and staff members in 6 grades with 5 classes per grade. The variant infectiousness, effectiveness of the mitigations, and the level of student vaccination were varied. The main outcomes looked at were the likelihood of at least 1 in-school transmission per month as well as the average increase in total monthly infections among the immediate school community that was linked with a reduction in mitigation.

The model showed that with a vaccination coverage rate of 70% or less for students along with just moderate assumptions for efficacy of mitigation strategies, the mitigation techniques could only be safely reduced when the local case incidence was 12 or fewer cases for 100,000 residents per day, which keeps the average additional cases tied to the reduction of mitigation to 5 or fewer cases per month. In order to reduce the possibility of any in-school transmission to less than 50% per month, the local case incidence would need to be 4 or fewer cases per 100,000 residents per day.

The investigators concluded that mitigation techniques such as masks or student vaccination were tied to significant reductions in both transmission and infections. The presence of a highly infectious variant and the degree to which it makes up cases in the community can have a significant role in the transmission of the disease. The amount of reduction in cases from mitigation and vaccination was impacted by the local incidence of COVID-19. The findings support developing plans that are tied to the rate of disease in the community as well as the local vaccination uptake.

Reference

1. Giardina J, Bilinski A, Fitzpatrick M, et al. Model-estimated association between simulated US elementary school–related SARS-CoV-2 transmission, mitigation interventions, and vaccine coverage across local incidence levels. JAMA Netw Open. 2022;5(2):e2147827. doi:10.1001/jamanetworkopen.2021.47827