Epidemiological characteristics of molecular transmission cluster among reported HIV/AIDS cases in Jiaxing city, Zhejiang province, 2017 / 中华流行病学杂志

Objective: To understand the epidemiological characteristics of one large HIV molecular transmission cluster in Jiaxing city, Zhejiang province, 2017 in order to select those people under high-risk and providing basis for programs on prevention. Methods: During 2017, newly diagnosed HIV/AIDS cases in this city were recruited. Plasma samples were collected from subjects, followed by RNA extraction, RT-PCR and nest-PCR for pol gene amplification, before being sequenced and aligned. Mega 6.0 software was used to construct phylogenetic tree, and Cytoscape 3.6.0 software was used to identify HIV molecular transmission clusters. Cases within the large transmission clusters were investigated, using a field-epidemiology-questionnaire. Data related to socio-demographics and previous sexual behaviors were collected and EpiData 3.0 and SPSS 20.0 software were used. Results: In the large transmission cluster with subtype identified as CRF07_BC, in Jiaxing, 2017, 26 cases of the total 30 cases were investigated. A total of 80.8% (21/26) could be identified as newly infected within the last two years and 30.8%(8/26) could be identified as newly infected within the last one year, including 22 cases infected locally. Among several infected cases who were at age 45 years or older, they admitted that they had experienced unprotected sexual contacts in local city for long time and having had more than 10 disclosed sexual contacts within the last two years at the local venues. Conclusions: This molecular cluster had been formed and scaled up quickly in recent two years, it has played an important role in promoting and scaling up the HIV transmission. Three cases identificed as high risk played an importantrde role in scaling up this cluster.

Survey of HIV infection in men who have sex with men living for 5 years or less in Wenzhou, Zhejiang province / 中华流行病学杂志

Objective: To assess the prevalence of HIV infection and related factors in men who have sex with men (MSM) living for ≤5 years in Wenzhou of Zhejiang province. Methods: MSM who were aged ≥16 years, had lived in Wenzhou for ≥3 months and had anal sex and/or oral sex with men in the last 12 months were recruited through respondent-driven sampling (RDS) from February to October in 2015. The MSM recruited completed a questionnaire for the information collection on socio-demographic characteristics, sexual behavior, awareness of HIV and related intervention, mental health status. Blood samples were collected from them for serological detection of HIV and syphilis antibodies. Software SPSS 18.0 was used to analyze HIV infection and related factors. Results: A total of 454 MSM were investigated, 108 of them (23.7%) were HIV positive. There were 267 MSM who lived in Wenzhou for ≤5 years, and 73 of them (27.3%) were HIV positive. Most of them were workers and commercial servants aged ≥25 years with personal monthly income <4 000 yuan and educational level of junior high school or below. According to multiple logistics regression analysis, age of 25-68 years old (OR=12.19, 95%CI: 2.29-65.02), heterosexual behavior in recent 6 months (OR=0.42, 95%CI: 0.18-0.96), believing it was possible to be infected with HIV (OR=0.06, 95%CI: 0.01-0.95), believing it was impossible to be infected with HIV (OR=0.03, 95%CI: 0.01-0.35) and syphilis status (OR=3.32, 95%CI: 1.05-10.52) were the risk factors associated with HIV infection. Conclusion: Compared with MSM who lived in Wenzhou for >5 years, MSM who lived in Wenzhou for ≤5 years had higher HIV infection rate and higher prevalence of risk behavior. It is necessary to conduct targeted intervention among them.