[Characteristics of subtypes and transmission of HIV-1 infected persons among student MSM in Zhejiang province, 2013-2015].

Objective: To investigate the characteristics of subtype diversity and transmission on HIV-1 among 12 to 30 years old student MSM in Zhejiang province. Methods: A total of 290 newly diagnosed HIV infected student MSM were selected as the research objects for molecular studies on HIV, in Zhejiang province during 2013 to 2015. Data on epidemiology and plasma samples of these people were collected. HIV-1 nucleotide sequences of pol gene regions were amplified using the RT-PCR/nested PCR method and sequenced. Phylogenetic analysis was performed to determine the HIV-1 genotypes. Characteristics of transmission mode among these cases were also analyzed. Results: A total of 290 cases, 50.3% were diagnosed in Hangzhou and 81.0% had college or above degrees. 178 sequences including 10 subtypes, were obtained, with the main subtypes as CRF01_AE (49.4%, 88/178) and CRF07_BC (39.3%, 70/178). A total of 18 molecular transmission clusters were formed (42 cases, cluster size from 2 to 4), with the proportions of clusters as 23.6% (42/178). 61.9% (26/42) of student MSM with their schools located in the same district within the transmission clusters. Their sexual partners would include both student MSM and non-student MSM. The proportion of clusters among middle school students was 38.2% (13/34), higher than that of college students (20.1%, 29/144) ( χ(2)=4.996, P<0.05). Conclusions: The HIV-1 subtypes of student MSM in Zhejiang province appeared diversity, which indicated with the diversity of sources of infection. The geographical distribution of cluster cases is relatively centralized. In order to effectively control the spread of AIDS, more attention should be paid to the sexual partners involved and to specific programs on intervention.