Spread dynamics of SARS-CoV-2 epidemic in China: a phylogenetic analysis

To reveal the detailed spread dynamics of SARS-CoV-2 epidemic in China, a phylogenetic analysis was performed by the Bayesian inference framework tool. 233 strains were retrieved from confirmed cases in China until March 31, 2020. The tMRCA of SARS-CoV-2 strains in China could be traced back to December 9, 2019. According to the effective population size curve reconstructed by Skyline model, this research revealed the influence of travel ban measures on the effective population size in China. Furthermore, we divided the epidemic process of SARS-CoV-2 in China into 4 stages according to the effective population size curve. With the Bayesian stochastic search variable selection method, phylogeographical reconstruction detailedly described the geographic spread behavior of SARS-CoV-2 in each stage and confirmed the importance of travel ban in blocking SARS-CoV-2 cross-regional spread. This article summarizes the influence of prevention and control measures in China, which has a positive impact on the world.