Characteristics and Outcomes of Pediatric COVID-19 Patients in Osaka, Japan.

The epidemiological information on characteristics, in-hospital treatments, and outcomes of the coronavirus disease 2019 (COVID-19) among pediatric patients has not been fully evaluated in Japan. This was a retrospective observational study conducted in the Osaka Prefecture, Japan, and we enrolled laboratory-confirmed COVID-19 patients aged ≤ 19 years old from January to November in 2020. Of 14,846 COVID-19 eligible patients, 1240 pediatric patients (8.4%) were registered during the study period; 329 were children aged 0-9 years (26.5%) and 911 were adolescents aged 10-19 years (73.5%). The majority of the patients exhibited mild symptoms at diagnosis (872, 70.3%), some were asymptomatic (296, 23.9%). Cluster infections occurred in child-care facilities (26, 7.9%) among children and in universities (27, 3.0%) and schools (18, 2.0%) among adolescents. The number of close-contact cases was 260 (69.0%) in children and 459 (50.4%) in adolescents. Sixty of the children (18.2%) and 90 of the adolescents (9.9%) were hospitalized. One patient received mechanical ventilation, and none underwent extracorporeal membrane oxygenation. One patient was admitted to the intensive care unit; there were no deaths. These results are useful for recognizing the clinical course from transmission route to outcomes of this infection in pediatric patients.