Epidemiological parameters of coronavirus disease 2019: a pooled analysis of publicly reported individual data of 1155 cases from seven countries

Shujuan Ma; Jiayue Zhang; Minyan Zeng; Qingping Yun; Wei Guo; Yixiang Zheng; Shi Zhao; Maggie H Wang; Zuyao Yang

The negative values of serial interval and time point of exposure provide evidence of presymptomatic transmission, which are consistent with the much shorter latent period than incubation period. The percentages of negative serial interval (3.92%) and negative time point of exposure (43.78%) can be viewed as the lower and upper limits of probability of presymptomatic transmission, respectively. Asymptomatic transmission was also observed in this study (Table 3 ). These findings are in line with those of previous studies. 8,9,14-17 Stratified analysis in this study found a trend towards longer incubation period of less severe cases as compared with that of more severe cases. This implies that severe cases could be detected and 'removed' from the pool of transmission sources more quickly, while less severe cases would All rights reserved. No reuse allowed without permission. the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.