Regional transmission pattern of HIV-1 Non-CRF01_AE strains circulating in Hebei province, China.

HIV-1 genetic diversity has recently been more and more complicated in Hebei province. To know about the transmission pattern of HIV-1 in Hebei, the phylogenetic analysis of non-CRF01_AE strains was performed using the maximum-likelihood (ML) method. Four clusters and two clusters were observed in the CRF07_BC and subtype B ML tree, respectively. Of these clusters, men who have sex with men (MSM) sequences were the most frequent, and no pure heterosexual cluster was found in this study. Our findings highlighted the close transmission relationship between the main HIV-1 non-CRF01_AE strains and the sexual exposure especially among MSM between neighboring provinces, such as Beijing and Liaoning, and Hebei. This provides new evidence that the main strains of HIV-1 were introduced into Hebei through sexual exposure especially among MSM from neighboring provinces, suggesting that it is urgent for us to take measures together with neighboring provinces to cut off HIV-1 dissemination chain through MSM.