Epidemiology and Transmission of COVID-19 in Shenzhen China: Analysis of 391 cases and 1,286 of their close contacts

Qifang Bi; Yongsheng Wu; Shujiang Mei; Chenfei Ye; Xuan Zou; Zhen Zhang; Xiaojian Liu; Lan Wei; Shaun A Truelove; Tong Zhang; Wei Gao; Cong Cheng; Xiujuan Tang; Xiaoliang Wu; Yu Wu; Binbin Sun; Suli Huang; Yu Sun; Juncen Zhang; Ting Ma; Justin Lessler; Teijian Feng

The maximum-likelihood estimates for the parametric distribution of the cumulative distribution function are shown, along with 1000 parametric bootstrap estimates of the cumulative distribution function. We estimate the median incubation period of COVID-19 is 4.8 days (95%CI, 4.2, 5.4). 5% of the cases who develop symptoms will do so by 1.6 days (95% CI, 1.3, 2.0) after infection, and 95% by 14.0 days (12.2, 15.9). We estimated that the median serial interval of COVID-19 is 5.4 days (95% CI, 4.4 to 6.5). 5% of the infected who develop symptoms will do so by 1.3 days (95% CI, 0.9 to 1.9) after symptom onset of the index case, and in 95% by 14.3 days (95% CI, 11.1 to 17.6).