Incidence of Omicron Variant Reinfection and Reduction of Reinfection Risk After Coronavirus Disease 2019 Vaccination in Children

Data are limited on the incidence of coronavirus disease 2019 (COVID-19) reinfection in children. This population-based cohort study in Niigata, Japan from January to November 2022 demonstrated the incidence of reinfection was 1337/48 099 (2.8%), and the hazard ratio for reinfection in vaccinated children was 0.29 (95% confidence interval, 0.20-0.40). From January to November 2022, 1337/48 099 (2.8%) children were reinfected by omicron variants of severe acute respiratory syndrome coronavirus 2 in Niigata, Japan. The risk of reinfection was reduced by completion of vaccination (hazard ratio 0.29, 95% confidence interval 0.20-0.40).