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We aimed to elucidate the characteristics of HIV molecular epidemiology and identify transmission hubs in eastern China using genetic transmission network and lineage analyses. HIV-TRACE was used to infer putative relationships. Across the range of epidemiologically-plausible genetic distance (GD) thresholds (0.1–2.0%), a sensitivity analysis was performed to determine the optimal threshold, generating the maximum number of transmission clusters and providing reliable resolution without merging different small clusters into a single large cluster. Characteristics of genetically linked individuals were analyzed using logistic regression. Assortativity (shared characteristics) analysis was performed to infer shared attributes between putative partners. 1,993 persons living with HIV-1 were enrolled. The determined GD thresholds within subtypes CRF07_BC, CRF01_AE, and B were 0.5%, 1.2%, and 1.7%, respectively, and 826 of 1,993 (41.4%) sequences were linked with at least one other sequence, forming 188 transmission clusters of 2–80 sequences. Clustering rates for the main subtypes CRF01_AE, CRF07_BC, and B were 50.9% (523/1027), 34.2% (256/749), and 32.1% (25/78), respectively. Median cluster sizes of these subtypes were 2 (2–52, n = 523), 2 (2–80, n = 256), and 3 (2–6, n = 25), respectively. Subtypes in individuals diagnosed and residing in Hangzhou city (OR = 1.423, 95% CI: 1.168–1.734) and men who have sex with men (MSM) were more likely to cluster. Assortativity analysis revealed individuals were more likely to be genetically linked to individuals from the same age group (AIage = 0.090, P<0.001) and the same area of residency in Zhejiang (AIcity = 0.078, P<0.001). Additionally, students living with HIV were more likely to be linked with students than show a random distribution (AI student = 0.740, P<0.01). These results highlight the importance of Hangzhou City in the regional epidemic and show that MSM comprise the population rapidly transmitting HIV in Zhejiang Province. We also provide a molecular epidemiology framework for improving our understanding of HIV transmission dynamics in eastern China. [ABSTRACT FROM AUTHOR]

Background: The upsurge in HIV infections among students is a matter of particular concern. However, few studies have explored the epidemiological characteristics including the risky sexual networking of HIV-infected students in Zhejiang province, China.Methods: Using the provincial surveillance data of HIV-infected students, we conducted a retrospective epidemiology study to describe the epidemiological characteristics of 628 newly diagnosed cases from 2011 to 2016 and detailed information of 124 cases from 2015 to 2016. Spatial analyses were conducted using ArcGIS software, and statistical analyses were performed using SPSS software.Results: A total of 628 cases of HIV/AIDS were diagnosed among students in Zhejiang Province, China between 2011 and 2016. The cases showed an overall increasing trend over time, while the proportions of students with HIV disease status, cases diagnosed by HIV voluntary counseling and testing (VCT), and cases of homosexual transmission remained stable over time. Significant spatial heterogeneity in the cases was seen at the county level. Detailed data on 124 HIV-positive individuals collected from the local Center for Disease Control and Prevention (CDC) from 2015 and 2016, showed that the majority of them (85.5%,) engaged in homosexual behavior, and 93.4% had sex with casual partners. These partners included not only social members, but also other students. Online dating applications represented the most common means of seeking and communicating with homosexual partners. The level of awareness regarding the risk of HIV infection, and the amount coverage of face-to-face education towards students were both low.Conclusions: HIV infections among students were characterized by increasing trend and spatial clustering in Zhejiang Province between 2011 and 2016, with homosexual sexual activity being the main mode of infection. Interventions are urgently required to prevent HIV infection in this population by increasing awareness of the disease. HIV testing programs and information regarding disease prevention specifically through online dating applications are needed. [ABSTRACT FROM AUTHOR]