Potential roles of social distancing in mitigating the spread of coronavirus disease 2019 (COVID-19) in South Korea

Sang Woo Park; Kaiyuan Sun; Cécile Viboud; Bryan T Grenfell; Jonathan Dushoff

Source Incubation period distribution Gamma(µ I , µ 2 I /σ 2 ) µ I ∼ Gamma(6.5 days, 145) σ ∼ Gamma(2.6, 25) [14] Generation-interval distribution NegativeBinomial(µ G , θ) µ G ∼ Gamma(5 days, 62) θ ∼ Gamma (5, 20) [15, 16] Table 1 : Assumed incubation and generation-interval distributions. Gamma distributions are parameterized using its mean and shape. Negative binomial distributions are parameterized using its mean and dispersion. Priors are chosen such that the 95% quantiles of prior means and standard deviations are consistent with previous estimates. decreased ( Fig. 2A) . Likewise, the estimates of R t gradually decrease and eventually drop below 1 about a week after the reporting of its first case, coinciding with the decrease in the metro traffic volume (Fig. 2C ). The initial decrease in R t may reflect behavior change within the church; the first confirmed case in Daegu became symptomatic on February 7, 2020, and visited the church on February 9 and 16, 2020 [2] . Our estimates of R t for Daegu are consistent with the estimates of R t for South Korea by Abbott et al. [17] -their estimates drop below 1 slightly later because they rely on number of symptomatic cases instead.