At that time, a study has found that reopening schools with in-person learning in the United States during the COVID-19 pandemic is associated with increased cases and death rates from the disease, particularly in places that do not require staff to wear masks at school
 
Governments and parents across the country have been debating about the possibility of reopening schools. At that time, a study has found that reopening schools with in-person learning in the United States during the COVID-19 pandemic is associated with increased case and death rates from the disease, particularly in places that do not require staff to wear masks at school.
 
Through a study published in the journal PNAS (Proceedings of the National Academy of Sciences), Hiroyuki Kasahara and colleagues examined county-level panel data from the United States between April 1 to December 2, 2020, correlating weekly COVID-19 cases and death rates with in-person school openings and mitigation measures in 14,703 school districts.
 
The authors reported that increased visits to both K-12 schools and colleges, measured by SafeGraph foot traffic data, were associated with a subsequent rise in cases and death rates, with fully-open K-12 learning associated with a five percentage-point increase in the growth rate of cases.
 
The link was pronounced for districts that did not require staff to wear masks at school. According to the authors, the findings support masking and other mitigation measures in schools, as well as the prioritisation of individuals in the education sector for vaccination.