2024 Yes https://doi.org/10.3201/eid3011.240638 Takayama, Yoshihiro Asia Observational Students Staff Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Viruses COVID rates This large-scale observational study in Okinawa used school-based PCR testing to estimate SARS-CoV-2 infection by school type and contact level. Despite many cases, low secondary transmission supports balancing public health with educational needs.