SARS-CoV-2 transmission in schools in Korea: nationwide cohort study.

<bold>Objective: </bold>There is an urgent public need to readdress the school closure strategies. We aimed to describe the epidemiology of COVID-19 in schools and school-aged children to understand their roles in transmitting SARS-CoV-2 in Korea.<bold>Design: </bold>Retrospective cohort study.<bold>Setting: </bold>All schools in Korea PATIENTS: All school-aged children in Korea.<bold>Interventions: </bold>None (observational study).<bold>Main Outcome Measures: </bold>Incidence rate, proportion of affected schools.<bold>Results: </bold>Between February and December 2020, the incidence rate was lower among school-aged children (63.2-79.8 per 100 000) compared with adults aged 19 and above (130.4 per 100 000). Household was the main route of transmission (62.3%), followed by community (21.3%) and school clusters (7.9%). Among the schools in Korea, 52% of secondary schools had COVID-19 cases, followed by 39% of primary schools and 3% of kindergartens.<bold>Conclusions: </bold>We found that schools and school-aged children aged 7-18 years were not the main drivers of COVID-19 transmission. The major sources of transmission were households. [ABSTRACT FROM AUTHOR]