Figure 1. Estimated serial interval distribution, incidence of coronavirus disease, and transmissibility during predominance of the Delta variant of severe acute respiratory syndrome coronavirus 2 in South Korea. A) Estimated serial interval distribution for 3,728 infector-infectee pairs. Solid blue line indicates fitted normal distribution; vertical bars indicate the distribution of empirical serial intervals. B) Reported number of confirmed coronavirus disease cases by date of symptom onset. Red vertical dashed line indicates the date of implementation of an enhanced social distancing, including limiting gathering sizes to 4 persons nationwide on July 19, 2021. C) Estimated daily Rt of severe acute respiratory syndrome coronavirus 2 (blue line) with 95% credible intervals (gray shade). Gray horizontal dashed line indicates the critical threshold of Rt = 1. Red vertical dashed line indicates the date of implementation of an enhanced social distancing. Rt, effective reproductive number.