Evaluation of COVID-19 epidemic outbreak caused by temporal contact-increase in South Korea

Objectives: On March 15, 2020, 61.3% of the confirmed cases of COVID-19 infection in South Korea are associated with the worship service that was organized on February 9 in the Shincheonji Church of Jesus in Daegu. We aim to evaluate the effects of mass infection in South Korea and assess the preventive control intervention. Method: Using openly available data of daily cumulative confirmed cases and deaths, the basic and effective reproduction numbers was estimated using a modified susceptible-exposed-infected-recovered-type epidemic model. Results: The basic reproduction number was estimated to be R-0 = 1.77. The effective reproduction number increased approximately 20 times after the mass infections from the 31 st patient, which was confirmed on February 9 in the Shincheonji Church of Jesus, Daegu. However, the effective reproduction number decreased to less than unity after February 28 owing to the implementation of high-level preventive control interventions in South Korea, coupled with voluntary prevention actions by citizens. Conclusion: Preventive action and control intervention were successfully established in South Korea. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.