[Characteristics and Trends of Coronavirus Disease 2019 Outbreak in the Republic of Korea (January 20, 2020-August 30, 2023)].

This report analyzes the characteristics of coronavirus disease 2019 (COVID-19) cases collected through mandatory surveillance between January 20, 2020 and August 30, 2023, by age, sex, and region. During the mandatory surveillance period, 34,572,554 cases, 35,605 deaths, and 38,112 severe/critical cases were recorded. The number of COVID-19 cases gradually increased in 2020 and 2021; however, the cases surged, with 82.2% of the pandemic's total cases reported in 2022, after the omicron variant became the dominant strain in January 2022. In March 2022, 9,959,368 cases were reported, accounting for the highest proportion (28.8%) of total cases. Individuals in their 40s (15.1%) and 30s (14.7%) represented the highest proportion of cases during the study period. Annually, the highest proportion of cases in 2020, 2021, 2022, and 2023 were observed among individuals in their 50s, 20s, 40s, and 30s, respectively. Regionally, metropolitan region accounted for 52.1% of the total cases. In non-metropolitan regions, most cases in 2020 were reported in Daegu and Gyeongbuk and increased in Busan, Ulsan, and Gyeongnam thereafter. This report complies with and conveys information on the characteristics of COVID-19 cases reported during the mandatory surveillance period. This report may serve as a reference for future respiratory infectious disease crises.