Objectives: A coronavirus disease (COVID-19) outbreak triggered by religious activities occurred in Daegu, South Korea in February 2020 . This outbreak spread rapidly to the community through high-risk groups . This study describes the characteristics of the COVID-19 cases based on S religious group membership and summarizes Daegu City's processes and responses to control the outbreak .
Methods: Epidemiologic characteristics of confirmed cases were obtained through basic and in-depth epidemiological surveys . General characteristics, asymptomatic proportion, case-fatality rates, and time-to-event within each group were presented after stratifying confirmed cases according to S religious group membership .
Results: Overall , 7,008 COVID-19 cases were confirmed in Daegu from February 18 to June 30 , 2020, and 61.5% (n=4,309) were S religious group members . Compared with non-members, members had a higher proportion of women (p <0.001), younger age (p <0.001), and lower disease prevalence . Asymptomatic cases included 38.4% of members and 23.7% of non-members (p <0.001) at the time of the investigation . The case-fatality rate of non-members aged & #8805; 60 years was significantly higher than that of members (p <0.001). Compared with non-members, the durations of symptom onset to diagnosis (p <0.001) and diagnosis to admission (p <0.001) of members were longer, whereas the duration of admission to discharge (p <0.001) was shorter . Conclusion: The epidemiologic features of S religious group members, including asymptomatic proportion, case-fatality rate, and time-to-event, differed from non-members . Daegu City prevented further spread of COVID-19 through immediate isolation and active screening tests of all S religious group members.