The Epidemic Dynamics of Four Major Lineages of HIV-1 CRF01_AE Strains After Their Introduction into China.

The epidemic of HIV-1 CRF01_AE in China was driven by multiple lineages of HIV-1 viruses introduced in the 1990s and increasing; it is important to investigate their epidemic status in China. In this study, we download all available CRF01_AE sequences (n = 2,931) from China and their associated epidemiological information in the Los Alamos HIV database for our analysis to explore their epidemic status in China. The results showed there were 11 distinct clusters of CRF01_AE strains in China, and 4 major clusters that accounted for 80.0% (1,793/2,241) of Chinese CRF01_AE strains in total had led a real epidemic. Clusters 1 and 2 were epidemic among heterosexuals and injecting drug users in southern and southwestern China, while Clusters 3 and 4 were predominant among homosexuals in eastern and central China and northeastern China, respectively. HIV-1 CRF01_AE strains detected in heterosexuals had the most complex characteristic, underscoring its important role in the occurrence of multiple CRF01_AE lineages. Furthermore, epidemic history reconstruction analysis using the birth-death susceptible-infected-removed package revealed that the four clusters had gone through varying epidemic stages. Clusters 2 and 3 were near the peak of the local epidemic, while Clusters 1 and 4 were just in the very early stage of their epidemic. The epidemic status of CRF01_AE clusters in the future is mainly determined by the effect of prevention and control. Our study provides new insights into the understanding of the epidemic dynamics of CRF01_AE in China.