Spatial and temporal variability in the transmission potential of COVID-19 in South Korea including the second wave in the greater Seoul area, February to July 2020

In South Korea, 13,745 cases of COVID-19 have been reported as of 19 July, 2020. We used EpiEstim R package to investigate the time-varying reproduction numbers of the COVID-19 in the four most affected regions in South Korea: Seoul, Gyeonggi Province, Gyeongbuk Province, and Daegu. At the regional level, Seoul and Gyeonggi Province have experienced two waves with the first major peak of COVID-19 in early March, followed by the second wave in the first two weeks of June, with reproduction numbers in early May greater than 3.0.

Gyeongbuk Province and Daegu are yet to experience a second wave of the disease, where the mean reproduction number reached values as high as 3.5-4.4. Our findings indicate that the loosening of the restrictions imposed by the government in May 2020 facilitated a second wave in the greater Seoul area.