2022 Yes https://onlinelibrary.wiley.com/doi/10.1111/ina.13142 McLeod, Robert S. Europe Observational Teachers Staff Students Air purification Infraction prophylaxis in school classrooms Masking and physical distancing Mechanical ventilation Natural ventilation In the presence of increasingly infectious SARS-Cov-2 variants, in-classroom teaching can only be safely maintained through a layered strategy combining multiple protective measures. The precise measures that are needed at any point in time depend upon a number of dynamic factors, including the specific threat-level posed by the circulating variant, the level of community infection, and the political acceptability of the resultant risk. By consistently implementing appropriate prophylaxis measures, evidence shows that the risk of infection from in-classroom teaching can be dramatically reduced.