HIV-1 epidemics among MSM are a major public health concern in China, especially in large cities. This study sought to better understand the dynamics of HIV molecular epidemiology among MSM in Shenzhen, a rapidly developing city with over 13.8 million people. HIV-1 pol sequences were obtained from 996 (53.5%) of 1862 HIV-infected MSM and 403(9.0%) of 4498 heterosexuals and injection drug users in Shenzhen, China from 2005-2012. Eight HIV-1 subtypes and some inter-subtype recombinants were identified among sampled MSM with CRF07_BC (39.1%) and CRF01_AE (35.1%) being the most predominant. From 2006 to 2012, the prevalence of CRF07_BC and CRF55_01B rapidly increased, while the prevalence of subtypes B and CRF01_AE gradually decreased. The genetic distances within CRF07_BC and CRF55_01B groups were significantly lower than within CRF01_AE and B groups. The vast majority (90.3%) of HIV-1 infected MSM in Shenzhen were migrants who came from 31 of the 34 provinces of China, and these migrants had significantly different HIV-1 subtype distributions from the local MSM. This study highlighted the importance of CRF07_BC and migrants in the changing HIV epidemic among MSM in China, and provides a molecular epidemiology framework for understanding how HIV-1 epidemics can change in large cities with diverse risk groups.

High-risk sexual practices were common among MSW regardless of their high level of HIV awareness. The working venues were associated with HIV infection and a recent test for HIV was a potential predictor of HIV infection. The time-location sampling method was found to be an appropriate way of recruiting MSW for this study, especially those without fixed working places.

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Money boys differed from ncMSM in the rate of HIV infection and some sexual characteristics and behaviors. Formatting separate interventions specifically targeting the 2 subgroups may be necessary.

Objectives: Shenzhen is suffering severe HIV epidemic. No systematic surveillance on high risk populations, HIV genetic diversity, transmitted drug resistance (TDR) and molecular transmission clusters (MTCs) have been reported yet. In this study, we described them based on newly diagnosed HIV positive cases from 2011 to 2018 in Shenzhen city, China. Methods: Plasma samples of newly reported HIV positive cases in Shenzhen, China were collected from 2011 to 2018. The HIV pol gene was amplified and sequenced for subtyping, genetic characterization, TDR and phylogenetic analysis. Demographic and risk characteristics associated with transmitted drug resistance-associated mutations (TDRAMs) and MTCs were explored by using logistic regression analyses. Results: 10,378 HIV pol sequences were successfully obtained from newly diagnosed patients with available background information. The most prevalent HIV-1 subtype was CRF07_BC (40.92%). CRF07_BC, CRF55_01B and URFs increased across years. Total TDR was 6.02% during 2011 to 2018. CRF01_AE, CRF08_BC, CRF55_01B and subtype B were more likely to be associated with TDRAMs than CRF07_BC. 4460 (42.98%) patients were infected with strains included in MTCs. Patients younger than 30 and over 50 years were more likely to cluster. Conclusions: The prevalence of HIV-1 drug resistance and molecular transmission clusters in Shenzhen should raise a high alert. Interventions targeting on patients with strains locating in MTCs should be considered to improve prevention effect in Shenzhen.