Temporal Changes in the Risk of Superspreading Events of Coronavirus Disease 2019

Abstract

To identify the temporal change in the possible risk of superspreading events, we estimated the overdispersion parameter in 2 different periods of the coronavirus disease 2019 pandemic. We determined that the possible risk of superspreading events was reduced 90% during the second epidemic period in South Korea.

Keywords: coronavirus; infectiousness; overdispersion; superspreading; transmission.

Figure 1.

Joint estimates of overdispersion parameter and reproductive number of coronavirus disease 2019. The red and blue lines indicate the 95% credible intervals of the estimated overdispersion parameter (k) in the first epidemic period (19 January–19 April 2020) and second epidemic period (20 April–16 October 2020), respectively. The posterior distributions of each parameter were plotted in the outer margin of each axis.

Figure 2.

The expected probabilities that the different numbers of index cases generate clusters of given size during (A) the first epidemic period (19 Jan–19 April 2020) , and (B) the second epidemic period (20 Apr–16 Oct 2020). Dashed, dotted, and long-dashed lines indicate the median estimates of the expected probabilities that 1, 5, and 10 infectors generate clusters of a given size, respectively. The green, red, and blue areas covered by solid lines indicate 95% credible intervals.