Chinese MSM Population Research Articles

Willingness to use long-acting injectable PrEP among HIV-negative/unknown men who have sex with men in mainland China: A cross-sectional online survey.

Men who have sex with men (MSM) are at high risk of HIV acquisition. Long-acting injectable-pre-exposure prophylaxis (LAI-PrEP), requiring less frequent dosing, is being studied as an alternative method to daily oral HIV PrEP. With the addition of this potential new prevention method, it expands the scope for a wider user choice and is expected to increase the acceptability and uptake of HIV prevention measures. The aim of our study was to explore the willingness to use LAI-PrEP and associated influential factors. Participants were recruited from December 2020 to March 2021 through banner advertisements on web- and mobile app-based platforms on Blued, a large gay Chinese social media platform. MSM in our cross-sectional study was HIV-negative and currently lived in mainland China. Participants were asked about their willingness to use LAI-PrEP and reasons why they might be or not be willing to use LAI-PrEP. Multivariable logistic regression was used to analyze the factors associated with the willingness to use LAI-PrEP. In total, 969 participants met the inclusion criteria and finished the survey. Nearly twenty percent (19.5%) of participants had never tested for HIV; 66.8% of MSM had multiple male partners; and 51.6% of MSM engaged in condomless sex with their partner. About three-fifths (66.3%) of MSM were aware of PrEP, and only 3.9% of MSM had used PrEP before. The willingness to use LAI-PrEP among MSM was 74.0% (95% CI: 71.4%-76.6%). MSM with higher education levels were less likely to show a willingness to use LAI-PrEP (AOR = 0.56, 95%CI: 0.38-0.84). Participants who had a history of HIV test (AOR = 1.68, 95%CI: 1.11-2.55), were willing to use daily oral PrEP (AOR = 10.64, 95%CI:7.43-15.21), had multiple male sexual partners (AOR = 1.33, 95%CI:0.93-1.90), who used rush popper(AOR = 1.49, 95%CI:1.05-2.13), and who were aware of PEP (AOR = 1.66, 95%CI: 1.02-2.70) were more likely to show willingness to use LAI-PrEP. In our study, MSM had quite high awareness but low uptake of PrEP. As LAI-PrEP is expected to be approved for use in China in the future, our study of MSM highlights the need for key population-focused education programs about PrEP and healthy sexual behavior. This study also provides some evidence for LAI-PrEP use among the Chinese MSM population in the future.

A structural equation modeling approach to investigate HIV testing willingness for men who have sex with men in China

BackgroundA substantial risk of contracting Human immunodeficiency virus (HIV) exists among men who have sex with men (MSM), and HIV infection rates have been rising. This study aimed to analyze the factors influencing the Chinese MSM population’s intention to test for HIV.MethodsNonprobability sampling techniques were employed in June 2022 to recruit MSM in Chongqing and Sichuan, China. The data were analyzed using structural equation modeling (SEM), which is based on the knowledge-attitude-behavior (KAB) theory.ResultsAmong 1687 participants, 964 (57.1%) of the MSM were willing to have an HIV test. The results of the structural equation modeling (SEM) showed that knowledge, attitude, and behavior all influenced the testing intention, with attitude having the greatest impact (total effect of 0.22).ConclusionHIV testing needs to be increased among MSM as they exhibit a moderate willingness to test. Improving education on HIV knowledge and risk behavior might enhance the willingness of MSM to test for HIV in China.

Biomedical association analysis between G2/M checkpoint genes and susceptibility to HIV-1 infection and AIDS progression from a northern chinese MSM population

BackgroundMSM are at high risk of HIV infection. Previous studies have shown that the cell cycle regulation plays an important role in HIV-1 infection, especially at the G2/M checkpoint. ATR, Chk1, Cdc25C and CDK1 are key genes of G2/M checkpoint. However, the association between SNPs of these genes and susceptibility to HIV-1 infection and AIDS progression remains unknown.MethodsIn this study, 42 tSNPs from the above four G2/M checkpoint genes were genotyped in 529 MSM and 529 control subjects from northern China to analyze this association.ResultsThe results showed that rs34660854 A and rs75368165 A in ATR gene and rs3756766 A in Cdc25C gene could increase the risk of HIV-1 infection (P = 0.049, OR = 1.234, 95% CI 1.001–1.521; P = 0.020, OR = 1.296, 95% CI 1.042–1.611; P = 0.011, OR = 1.392, 95% CI 1.080–1.794, respectively), while Chk1 rs10893405 (P = 0.029, OR = 1.629, 95% CI 1.051–2.523) were significantly associated with AIDS progression. Besides, rs34660854 (P = 0.019, OR = 1.364, 95% CI 1.052–1.769; P = 0.022, OR = 1.337, 95% CI 1.042–1.716, under Codominant model and Dominant model, respectively) and rs75368165 (P = 0.006, OR = 1.445, 95% CI = 1.114–1.899; P = 0.007, OR = 1.418, 95% CI 1.099–1.831, under Codominant model and Dominant model, respectively) in ATR gene, rs12576279 (P = 0.013, OR = 0.343, 95% CI 0.147-0.800; P = 0.048, OR = 0.437, 95% CI 0.192–0.991, under Codominant model and Dominant model, respectively) and rs540436 (P = 0.012, OR = 1.407, 95% CI 1.077–1.836; P = 0.021, OR = 1.359, 95% CI 1.048–1.762, under Codominant model and Dominant model, respectively) in Chk1 gene, rs3756766 (P = 0.013, OR = 1.455, 95% CI 1.083–1.954; P = 0.009, OR = 1.460, 95% CI 1.098–1.940, under Codominant model and Dominant model, respectively) in Cdc25C gene and rs139245206 (P = 0.022, OR = 5.011, 95% CI 1.267–19.816; P = 0.020, OR = 5.067, 95% CI 1.286–19.970, under Codominant model and Recessive model, respectively) in CDK1 gene were significantly associated with HIV-1 infection under different models.ConclusionsWe found that genetic variants of G2/M checkpoint genes had a molecular influence on the occurrence of HIV-1 infection and AIDS progression in a northern Chinese MSM population.

Association of Polymorphisms in NHEJ Pathway Genes with HIV-1 Infection and AIDS Progression in a Northern Chinese MSM Population.

Background and Aims Men who have sex with men (MSM) are at high risk of HIV infection. The nonhomologous end joining (NHEJ) pathway is the main way of double-stranded DNA break (DSB) repair in the higher eukaryotes and can repair the DSB timely at any time in cell cycle. It is also indicated that the NHEJ pathway is associated with HIV-1 infection since the DSB in host genome DNA occurs in the process of HIV-1 integration. The aim of the present investigation was to evaluate associations of single-nucleotide polymorphisms (SNPs) in NHEJ pathway genes with susceptibility to HIV-1 infection and AIDS progression among MSM residing in northern China. Methods A total of 481 HIV-1 seropositive men and 493 HIV-1 seronegative men were included in this case-control study. Genotyping of 22 SNPs in NHEJ pathway genes was performed using the SNPscan™ Kit. Results Positive associations were observed between XRCC6 rs132770 and XRCC4 rs1056503 genotypes and the susceptibility to HIV-1 infection. In gene-gene interaction analysis, significant SNP-SNP interactions of XRCC6 and XRCC4 genetic variations were found to play a potential role in the risk of HIV-1 infection. In stratified analysis, XRCC5 rs16855458 was significantly associated with CD4+ T cell counts in AIDS patients, whereas LIG4 rs1805388 was linked to the clinical phases of AIDS patients. Conclusions NHEJ gene polymorphisms can be considered to be risk factors of HIV-1 infection and AIDS progression in the northern Chinese MSM population.

Association of APEX1 and XRCC1 Gene Polymorphisms With HIV-1 Infection Susceptibility and AIDS Progression in a Northern Chinese MSM Population.

Background: Some studies have shown that the base excision repair (BER) pathway has an effect on HIV-1 replication. APEX1 and XRCC1 as key BER genes may affect DNA repair capacity. However, the roles of single nucleotide polymorphisms (SNPs) in APEX1 and XRCC1 and their impact on HIV-1 infection and AIDS progression remain unclear. Methods: A custom-designed 48-Plex SNPscan Kit was used for detection of single nucleotide polymorphisms. 601 HIV-1-infected men who have sex with men (MSM) and 624 age-matched healthy individuals were recruited in northern China. Four SNPs (rs1130409, rs1760944, rs2307486 and rs3136817) in APEX1 gene and three SNPs (rs1001581, rs25487 and rs25489) in XRCC1 gene were genotyped. The generalized multifactor dimension reduction (GMDR) method was used to identify the SNP-SNP interactions. Results: In this study, rs1130409 G allele, rs1001581 C allele and rs25487 C allele were associated with a higher risk of HIV-1 infection susceptibility (p = 0.020, p = 0.007 and p = 0.032, respectively). The frequencies of APEX1 haplotype TT and XRCC1 haplotype CT showed significant differences between cases and controls (p = 0.0372 and p = 0.0189, respectively). Interestingly, stratified analysis showed that the frequency of rs1001581 C allele was significantly higher in AIDS patients with the CD4+ T-lymphocyte count <200 cells/μl than those with >200 cells/μl (p = 0.022). Moreover, significant gene-gene interactions among rs1130409, rs1001581 and rs25487 were identified by GMDR (p = 0.0107). Specially, individuals with five to six risk alleles have a higher susceptibility to HIV-1 infection than those with zero to two risk alleles (p < 0.001). Conclusion: APEX1 and XRCC1 gene polymorphisms were associated with the susceptibility to HIV-1 infection and AIDS progression in MSM populations in northern China.

Meta analysis on acceptance rate of HIV pre-exposure prophylaxis among men who have sex with men in China

Objective: To systematically evaluate the acceptance of pre-exposure prophylaxis (PrEP)among men who have sex with men (MSM) in China, so as to provide reference for the promotion of preventive drug use before human immunodeficiency virus exposure in China. Methods: By searching the databases of China national knowledge infrastructure, VIP database, Wanfan knowledge service platform, PubMed, Web of Science, Embase and The Cochrane Library with key words of "men who have sex with men" "pre-exposure prophylaxis" "PrEP" and "MSM". The literature on the willingness of Chinese MSM population to accept PrEP was systematically collected, and the data of the literature meeting the inclusion criteria were extracted for Meta analysis. Results: A total of 12 articles were selected in this study, including 6 articles in English and 6 in Chinese. The score of bias risk assessment of eligible articles was 14-18, which was more than 70% of the total score. The total number of samples was 11 269. The overall acceptance rate of PrEP was 0.77(95%CI:0.71-0.82). In subgroup analysis, the acceptance rates of different nationalities, marriage, household registration, age, education background, income, sexual orientation, sexual behavior and awareness of PrEP were statistically significant. Conclusion: In general, the acceptance rate of PrEP in MSM population is higher, but the awareness rate is low. There are differences in the acceptance rate among different groups.

Location inference for hidden population with online text analysis

BackgroundUnderstanding the geographic distribution of hidden population, such as men who have sex with men (MSM), sex workers, or injecting drug users, are of great importance for the adequate deployment of intervention strategies and public health decision making. However, due to the hard-to-access properties, e.g., lack of a sampling frame, sensitivity issue, reporting error, etc., traditional survey methods are largely limited when studying such populations. With data extracted from the very active online community of MSM in China, in this study we adopt and develop location inferring methods to achieve a high-resolution mapping of users in this community at national level.MethodsWe collect a comprehensive dataset from the largest sub-community related to MSM topics in Baidu Tieba, covering 628,360 MSM-related users. Based on users’ publicly available posts, we evaluate and compare the performances of mainstream location inference algorithms on the online locating problem of Chinese MSM population. To improve the inference accuracy, other approaches in natural language processing are introduced into the location extraction, such as context analysis and pattern recognition. In addition, we develop a hybrid voting algorithm (HVA-LI) by allowing different approaches to vote to determine the best inference results, which guarantees a more effective way on location inference for hidden population.ResultsBy comparing the performances of popular inference algorithms, we find that the classic gazetteer-based algorithm has achieved better results. And in the HVA-LI algorithms, the hybrid algorithm consisting of the simple gazetteer-based method and named entity recognition (NER) is proven to be the best to deal with inferring users’ locations disclosed in short texts on online communities, improving the inferring accuracy from 50.3 to 71.3% on the MSM-related dataset.ConclusionsIn this study, we have explored the possibility of location inferring by analyzing textual content posted by online users. A more effective hybrid algorithm, i.e., the Gazetteer & NER algorithm is proposed, which is conducive to overcoming the sparse location labeling problem in user profiles, and can be extended to the inference of geo-statistics for other hidden populations.

Evolutionary characteristics and genetic transmission patterns of predominant HIV-1 subtypes among men who have sex with men in China

ObjectivesMen who have sex with men (MSM) represent one of the major risk groups for HIV-1 infection in China, and the predominant subtypes among this population has changed over the last two decades. The objective of this study was to determine the evolutionary characteristics and transmission patterns of the dominant HIV-1 strains in the Chinese MSM population. MethodsA total of 4980 published HIV-1 pol gene sequences from MSM in China were retrieved and comprehensive evolutionary and transmission analyses were then conducted. Bayesian coalescent-based methods and selection pressure analyses were used to reconstruct the time-scale and demographic history and to estimate other evolutionary parameters. Transmission patterns were characterized using network analyses. ResultsThere were 2546 (51.12%) CRF01_AE, 1263 (25.36%) CRF07_BC, and 623 (12.51%) subtype B, accounting for 88.99% of the total sequences. From 2000 to 2016, the prevalence of CRF01_AE was stable, comprising nearly half of all sequences over time (58.33–45.38%, p=0.071). CRF07_BC increased slightly from 13.3% to 22.49% (p<0.001), while subtype B decreased dramatically from 41.67% to 9.04% (p<0.001). Demographic reconstruction showed that the greatest expansion of the HIV epidemic occurred between 1999 and 2005. CRF01_AE had a higher estimated evolutionary rate (2.97×10−3 substitutions/site/year) and exhibited more sites under positive selection (25/351 codons) compared to the other subtypes. Network analyses showed that CRF07_BC (68.29%, 84/123) had a higher proportion of cross-region networks than CRF01_AE (49.1%, 174/354) and subtype B (36.46%, 35/96) (p<0.001). ConclusionsThe predominant subtypes of HIV-1 in Chinese MSM have different evolutionary characteristics and transmission patterns, which poses a significant challenge to HIV treatment and disease prevention.

Association between polymorphisms in MRE11 and HIV-1 susceptibility and AIDS progression in a northern Chinese MSM population.

Previous studies reported that DNA damage repair (DDR) genes may play an important role in HIV-1 infection. The MRE11 gene, a member of the MRN complex, plays an essential part in the homologous recombination pathway, which is one of the classical DDR pathways. Previous reports have demonstrated that MRE11 has an effect on HIV-1 replication. However, the role of SNPs in the MRE11 gene and their impact on HIV-1 infection and AIDS progression remain unknown. In this study, 434 MSM HIV-1-infected patients in northern China and 431 age-matched healthy controls were enrolled. Five SNPs (rs2155209, rs10831234, rs13447720, rs601341 and rs11020803) at the MRE11 gene were genotyped. Another series of cases (409 MSM HIV-1-infected patients) and controls (403 age-matched healthy males) were recruited as the validation set. In our study, rs10831234 showed differences in allele frequencies between cases and controls (P = 0.005). Additionally, there was an association between rs10831234 and HIV-1 infection susceptibility in dominant and additive models (P = 0.005 and P = 0.006, respectively). All significant associations were replicated in the validation set, and the associations were still significant after Bonferroni correction for multiple testing when the two data sets were combined. Furthermore, in haplotype association analyses between the case and control groups, the frequencies of the haplotypes Crs11020803Crs10831234 and Trs11020803Trs10831234 showed significant differences (P = 0.0181 and P = 0.0068, respectively). We demonstrated that the MRE11 rs10831234-T allele may confer increased risk of HIV-1 infection.

Characterization of a New HIV-1 CRF01_AE/B Recombinant Virus Form Among Men Who Have Sex with Men in Shanghai, China.

To date, there are 16 types of CRF01_AE/B circulating recombinant forms identified, and most of them are distributed in Asian countries such as China, Malaysia, and Singapore. Previous HIV molecular epidemiological surveys showed that CRF01_AE (27.6%) and B (9.6%) subtypes are predominant strains in mainland of China. At the same time, the HIV-1 virus spreads faster in the men who have sex with men (MSM) population than in other risk groups. In Shanghai district, ∼66.0% of newly reported cases were infected through homosexual transmission. In this study, we report a novel recombinant strain of CRF01_AE/B. The near full-length genome phylogenetic tree showed that the strain clustered with the CRF01_AE reference sequence and placed in the peripheral position within the branch of the CRF01_AE strain. Subregional evolutionary results indicated that the CRF01_AE subtype was derived from cluster 4 of CRF01_AE, which is mainly distributed in northern China. The subtype B was correlated with the U.S./Europe B, which are widely prevalent in the Chinese MSM population. In recent years, a large number of recombinant forms between CRF01_AE and B strains are continuously emerging in China. Therefore, understanding the current epidemic recombinant forms will have significant implications for prevention and treatment of HIV/AIDS.

Quality of life among men who have sex with men in China measured using the 36-item Short-Form Health Survey: A cross-sectional study.

The present study was conducted to assess the quality of life (QOL) of Chinese men who have sex with men (MSM) and to explore possible factors associated with QOL among them.A cross-sectional study of 370 MSM in Dalian and Huludao city was conducted to evaluate QOL in MSM using the Chinese version of the 36-item Short-Form Health Survey (SF-36). A t test was used to compare the QOL score of our sample with the Chinese norm. ANOVA, t test, and multivariate linear regression analysis were used to assess the association of QOL with basic characteristics.The QOL score of MSM was lower than the Chinese norm (P < .05). Multivariate analysis showed that marital status and monthly income were factors associated with physical component summary (PCS) and mental component summary (MCS) among MSM population (P < .05). Married MSM had poorer QOL, and respondents with higher income levels had better QOL.The government may need to develop more effective prevention strategies to improve the mental component of QOL in the Chinese MSM population, especially the married MSM population.

Near Full-Length Genome Sequence of a Novel HIV-1 Second-Generation Recombinant Form (CRF01_AE/CRF07_BC) Detected Among Blood Donors in North China.

In this study, a novel CRF01_AE/07_BC HIV-1 recombinant form, with five breakpoints in the pol, vpr, env, and nef gene regions, was identified from a voluntary blood donor in North China. Our study showed that this HIV-1 recombinant form might be a second-generation recombinant form from two predominant strains in the men who have sex with men (MSM) population, with the CRF07_BC fragments belonging to a CRF07_BC lineage specific to Chinese MSM and the CRF01_AE fragments belonging to the CRF01_AE lineage 5 common among MSM in northern China. Our findings supported the high-risk blood donation behaviors of MSM, implied the increasing complexity of the HIV-1 epidemic among the Chinese MSM population, and called more attention to the effectiveness of the screening test for the growing number of new HIV-1 recombinant forms.

Sexual behaviors and HIV/syphilis testing among transgender individuals in China: implications for expanding HIV testing services.

HIV and syphilis are disproportionately common among transgender individuals globally, yet few studies have investigated transgender HIV/syphilis risk and testing in low- and middle-income nations. We conducted an online survey of men who have sex with men (MSM) and transgender individuals to examine sexual behaviors and HIV/syphilis testing in China. We recruited MSM and transgender individuals from 2 major Chinese lesbian, gay, bisexual, and transgender Web platforms. χ Test and logistic regression were used to compare risk behaviors, HIV and syphilis testing history, and prevalence between transgender individuals and other MSM. Among the 1320 participants, 52 (3.9%) self-identified as transgender. Demographics, including education, employment, and marital status, were similar between both groups, whereas transgender individuals were older. Condomless anal intercourse rate was comparable between the groups. Transgender individuals were less likely to report ever testing for HIV (34.6% vs. 62.0%) and syphilis (15.7% vs. 31.2%) with adjusted odds ratios of 0.36 (95% confidence interval, 0.20-0.65) and 0.42 (95% confidence interval, 0.20-0.91), respectively. We found a trend toward a higher HIV prevalence among transgender individuals (11.1% vs. 5.7%, P = 0.12). Transgender individuals have suboptimal HIV and syphilis testing rates in China. Given the substantial risk behaviors and burden of HIV/STI in the general Chinese MSM population and a lack of knowledge about transgender individuals, enhanced HIV/syphilis testing programs for transgender individuals in China are needed.

HIV and Syphilis Prevalence Among Men Who Have Sex With Men: A Cross-Sectional Survey of 61 Cities in China

Human immunodeficiency virus (HIV) has rapidly spread among men who have sex with men (MSM) in China in recent years; the magnitude of the epidemic is unclear. We sought to test 3 hypotheses: (1) The prevalence of both HIV and syphilis among MSM in China is high, (2) the 2 epidemics each have unique geographical distributions, and (3) demographic and sexual behavior characteristics are different among segments of the MSM population in China. A total of 47 231 MSM from 61 cities in China participated in a cross-sectional survey conducted from February 2008 to September 2009. Demographic and behavioral data were collected and analyzed and blood samples tested for HIV and syphilis. Three subgroups among the broader MSM sample were described. Main outcome measures were HIV and syphilis prevalence. An overall prevalence of 4.9% (2314/47 231; 95% confidence interval [CI], 4.7%-5.1%) for HIV and 11.8% (5552/47 231; 95% CI, 11.5%-12.0%) for syphilis was found. Syphilis-positive MSM had the highest HIV prevalence, 12.5% (693/5552; 95% CI, 11.6%-13.4%). However, correlations between HIV and syphilis prevalence were found in only 3 of 6 geographical regions (Northwest: r = 0.82, P = .0253; East: r = 0.78, P = .0004; and South-central: r = 0.63, P = .0276). Three subgroups-nonlocal MSM, Internet-using MSM, and female-partnering MSM-were found to have different profiles of characteristics and behaviors. HIV and syphilis prevalences among MSM in China are high and the 2 epidemics are largely separate geographically. Three segments of the Chinese MSM population each have different demographic and sexual risk "profiles" that suggest high potential for bridging infection across geographies, generations, and sexes.

New emerging recombinant HIV-1 strains and close transmission linkage of HIV-1 strains in the Chinese MSM population indicate a new epidemic risk.

In recent years, the population of men who have sex with men (MSM) have become the most significant increasing group of HIV-1 transmission in China. To identify new recombinant strains and transmission patterns of HIV-1 in Chinese MSM population, a cross-sectional investigation of MSM in Anhui Province (in south-eastern China) was performed in 2011. The diagnosed AIDS case rate, CD4 T-cell counts, HIV subtypes, and origin of the recombinant strains were investigated in 138 collected samples. The phylogenetic and bootscan analyses demonstrated that, apart from three previously reported circulating strains (CRF07_BC, CRF01_AE, subtype B), various recombinant strains among subtype B, subtype C, CRF01_AE, and CRF07_BC were simultaneously identified in Chinese MSM for the first time. The introducing time of B subtype in Chinese MSM populations was estimated in 1985, CRF01_AE in 2000, and CRF07_BC in 2003; the latter two account for more than 85% of MSM infections. Notably, in comparison with B subtype infections in Anhui MSM, CRF01_AE, with the highest prevalence rate, may accelerate AIDS progression. Over half of patients (56%) infected with new recombinant strains infection are diagnosed as progression into AIDS. Both Bayes and phylogenetic analyses indicated that there was active HIV transmission among MSM nationwide, which may facilitate the transmission of the new 01B recombinant strains in MSM. In conclusion, new recombinant strains and active transmission were identified in the Chinese MSM population, which may lead to a new alarming HIV pandemic in this population due to the increased pathogenesis of the newly emerging strains.

Identification of Subtype B, Multiple Circulating Recombinant Forms and Unique Recombinants of HIV Type 1 in an MSM Cohort in China

To study HIV-1 genetic diversity among HIV-positive men who have sex with men (MSM) in China, a cohort consisting of HIV-positive MSM was established in 2005 and was monitored every 2 years. In 2007, 44 HIVpositiveMSM subjects were genotyped, and the results showed HIV-1 subtype B decreased from 77.5% to41.9%, but non-B subtypes increased rapidly represented by CRF01_AE from 3.7% to 30.2% compared to 2005.In addition, one case of CRF07_BC was first identified in this population, which mainly circulated among HIV-1-infected injection drug users (IDUs) in China. There were 11 unique recombinant forms (URFs) consisting ofa recombination of CRF01_AE with subtype B or CRF07_BC. The subtype-specific phylogenic tree analysis showed that the genetic distance within subtype B group viruses was larger than the genetic distance within the CRF01_AE group (p 0.001). Of the identified viruses in the Chinese MSM population, over 80% of subtype B viruses might originate from the United States and Brazil, and over 85% of the CRF01_AE viruses mightoriginate from Thailand. In addition, epidemic study data showed that some of the HIV-1-infected MSM had foreign sexual partners (13.6%) and heterosexual activities (43.2%). The patients infected with HIV-1 URF viruses had more heterosexual encounters (54.5%) and more sexual partners (72.7%) compared to those infected with subtype B (44.4%; 33.3%) and CRF01_AE (23.1%; 69.2%) viruses. Taken together, we suspected that the genetic complexity of HIV-1 viruses identified in Chinese MSM populations was more likely a result of multiple introductions of viruses from the general population infected with HIV-1 through IDUs or heterosexual transmission.