Limited transmission of COVID-19 from open schools but teachers were affected: Swedish study

In Sweden, upper-secondary schools moved online while lower-secondary schools remained open during the spring of 2020. A comparison of parents with children in the final year of lower-secondary and first year of upper-secondary school shows that keeping the former open had limited consequences for the overall transmission of the virus. However, the infection rate doubled among lower-secondary teachers relative to upper-secondary ones.

source https://www.sciencedaily.com/releases/2021/02/210212101842.htm