Features of COVID-19 Among Children and Adolescents Without Risk Factors Before and After the Delta Variant Outbreak in South Korea. Issue 1 (January 2022) - Ryu, Byung-Han; Hong, Sun In; Lim, Su Jin; Cho, Younghwa; Hong, Kyung-Wook; Bae, In-Gyu; Cho, Oh-Hyun