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1.
HIV antibody testing is a key measure of HIV prevention for men who have sex with men (MSM). The World Health Organization recommends sexually active and at-risk MSM to take up HIV antibody testing regularly. This study aimed to investigate the prevalence of behavioral intention to take up HIV antibody testing in the next six months among Hong Kong MSM who were ever-testers. An anonymous cross-sectional survey recruited 326 MSM who had taken up HIV antibody testing from gay-friendly venues and internet in Hong Kong. Of the participants, 40.8% had had unprotected anal intercourse with regular or non-regular male sex partners in the last six months; they were at risk of HIV transmission despite experience in HIV antibody testing. Only 37.2% showed a strong intention to take up HIV antibody testing again in the next six months. Adjusted analysis showed that both perceived discrimination toward Hong Kong MSM (AOR = .60, 95% CI: .36–.98) and the CARE Measure assessing perceived empathy of service providers (AOR = 1.05, 95% CI: 1.02–1.08) were significantly associated with intention for retesting. Perceived discrimination, however, became statistically non-significant (AOR = .68, 95% CI: .41–1.14), when both CARE Measure and perceived discrimination entered into the adjusted model. It is warranted to increase HIV retesting rate by removing perceived discrimination and reducing the negative effect of perceived discrimination through enhancement of empathy of service providers.  相似文献   

2.
BackgroundHuman Papilloma Virus (HPV) infection is the most common sexually transmitted viral infection worldwide. HPV is highly prevalent in sexually active men who have sex with men (MSM) and has been associated with anal cancer, penile cancer, and oropharyngeal cancer.MethodsFrom March to September 2011, we conducted a cross-sectional study of HPV prevalence among MSM above age 18 years. Participants were recruited using respondent driven sampling at Clinica Cayetano Heredia. All participants provided anal, genital, and oral samples for HPV DNA testing, and blood for HIV and HPV antibody testing.ResultsA total of 200 MSM were recruited in the study. The mean age was 34 years (range 18–59 years, SD = 9.4) and101 participants were HIV negative (99 HIV positive). HPV 6/11/16/18 or quadrivalent HPV vaccine (HPV4) genotype seroprevalence among HIV negative and positive MSM was 64.3% (55%-75.9%) and 93.8% (87.6%-99.2%) respectively (p<0.001). HIV positivity was associated with a higher prevalence of HPV4 and HPV 16/18 DNA at external genital sites and the anal canal. HPV4 DNA prevalence at external genital sites among HIV negative and positive MSM was 14.9% and 28.7% (p = 0.02) respectively, at anal canal was 50.9% and 79.0% (p = 0.001), and at the oral cavity was 9.9% and 8.5% (p = 0.6).ConclusionsHPV4 seroprevalence was high in our study among both HIV positives and negatives, with HPV DNA prevalence much lower, and the anal canal being the anatomical site with the highest HPV DNA prevalence. HPV prevention interventions are needed among MSM at high-risk for HIV infection.  相似文献   

3.
To determine HIV prevalence and associated risk factors among men who have sex with men (MSM) in Abidjan, Côte d’Ivoire. We conducted a cross-sectional RDS survey of MSM in Abidjan from October 2011 to February 2012. Eligibility criteria included age ≥ 18 years and having had oral or anal sex with another man in the last 12 months. Weighted data analysis was conducted with RDSAT and SAS. We enrolled 603 participants, of whom 601 (99.7%) completed the questionnaire and 581 (96.7%) consented to HIV testing. HIV population prevalence was estimated as 18.0% (95% CI: 13.0-23.1); 86.4% (95% CI: 75.1-94.9) of HIV-positive MSM were unaware of their serostatus. In multivariable analysis, adjusting for age, education, and income, HIV infection was associated with unprotected sex at last sex with a woman, more than two male anal sex partners in last 12 months, inconsistent condom use during anal sex with a man, self-perceived risk of HIV, history of forced sex, history of physical abuse due to MSM status, and not receiving last HIV test result prior to study. HIV prevalence among MSM in Abidjan is more than four times as high as that of general population men. MSM engage in high-risk sexual behavior and most HIV-positive MSM are unaware of their serostatus. Greater access to HIV prevention, care, and treatment services targeted to MSM is necessary.  相似文献   

4.
Chen JH  Wong KH  Chan KC  To SW  Chen Z  Yam WC 《PloS one》2011,6(9):e25286
The men-having-sex-with-men (MSM) population has become one of the major risk groups for HIV-1 infection in the Asia Pacific countries. Hong Kong is located in the centre of Asia and the transmission history of HIV-1 subtype B transmission among MSM remained unclear. The aim of this study was to investigate the transmission dynamics of HIV-1 subtype B virus in the Hong Kong MSM population. Samples of 125 HIV-1 subtype B infected MSM patients were recruited in this study. Through this study, the subtype B epidemic in the Hong Kong MSM population was identified spreading mainly among local Chinese who caught infection locally. On the other hand, HIV-1 subtype B infected Caucasian MSM caught infection mainly outside Hong Kong. The Bayesian phylogenetic analysis also indicated that 3 separate subtype B epidemics with divergence dates in the 1990s had occurred. The first and latest epidemics were comparatively small-scaled; spreading among the local Chinese MSM while sauna-visiting was found to be the major sex partner sourcing reservoir for the first subtype B epidemic. However, the second epidemic was spread in a large-scale among local Chinese MSM with a number of them having sourced their sex partners through the internet. The epidemic virus was estimated to have a divergence date in 1987 and the infected population in Hong Kong had a logistic growth throughout the past 20 years. Our study elucidated the evolutionary and demographic history of HIV-1 subtype B virus in Hong Kong MSM population. The understanding of transmission and growth model of the subtype B epidemic provides more information on the HIV-1 transmission among MSM population in other Asia Pacific high-income countries.  相似文献   

5.

Background

Further research is necessary to understand the factors contributing to the high prevalence of HIV/STIs among men who have sex with men (MSM) in Peru. We compared HIV/STI prevalence and risk factors between two non-probability samples of MSM, one passively enrolled from an STI clinic and the other actively enrolled from community venues surrounding the clinic in Lima, Peru.

Methods

A total of 560 self-identified MSM were enrolled between May-December, 2007. 438 subjects enrolled from a municipal STI clinic and 122 subjects enrolled during community outreach visits. All participants underwent screening for HIV, syphilis, HSV-2, gonorrhoea, and chlamydia and completed a survey assessing their history of HIV/STIs, prior HIV testing, and sexual behavior.

Results

HIV prevalence was significantly higher among MSM enrolled from the clinic, with previously undiagnosed HIV identified in 9.1% compared with 2.6% of community participants. 15.4 % of all MSM screened were infected with ≥1 curable STI, 7.4% with early syphilis (RPR≥1∶16) and 5.5% with urethral gonorrhoea and/or chlamydia. No significant differences between populations were reported in prevalence of STIs, number of male sex partners, history of unprotected anal intercourse, or alcohol and/or drug use prior to sex. Exchange of sex for money or goods was reported by 33.5% of MSM enrolled from the clinic and 21.2% of MSM from the community (p = 0.01).

Conclusions

Our data demonstrate that the prevalence of HIV and STIs, including syphilis, gonorrhoea, and chlamydia are extremely high among MSM enrolled from both clinic and community venues in urban Peru. New strategies are needed to address differences in HIV/STI epidemiology between clinic- and community-enrolled samples of MSM.  相似文献   

6.
目前我国人类免疫缺陷病毒(HIV)感染疫情总体处于低流行水平,但男男性行为(MSM)人群中HIV感染呈现快速上升趋势,传播亚型呈现出新的特点,疾病进展较快。HIV核酸及抗原抗体检测等手段对早期发现MSM人群中HIV感染者具有重要意义。解析MSM人群艾滋病疾病进展的影响因素,发现新的生物学标记,可为早期评估HIV感染的预后提供创新性手段。早期发现我国MSM人群中HIV感染者和抗病毒治疗等综合干预,对我国艾滋病流行的控制具有重要意义。  相似文献   

7.
ObjectivesThis study estimates HIV prevalence among men who have sex with men (MSM) in Jamaica and explores social determinants of HIV infection among MSM.DesignAn island-wide cross-sectional survey of MSM recruited by peer referral and outreach was conducted in 2011. A structured questionnaire was administered and HIV/STI tests done. We compared three groups: MSM who accepted cash for sex within the past 3 months (MSM SW), MSM who did not accept cash for sex (MSM non-SW), and MSM with adverse life events (ever raped, jailed, homeless, victim of violence or low literacy).ResultsHIV prevalence among 449 MSM was 31.4%, MSM SW 41.1%, MSM with adverse life events 38.5%, 17 transgender MSM (52.9%), and MSM non-SW without adverse events 21.0%. HIV prevalence increased with age and number of adverse life events (test for trend P < 0.001), as did STI prevalence (P = 0.03). HIV incidence was 6.7 cases/100 person-years (95% CI: 3.74, 12.19). HIV prevalence was highest among MSM reporting high-risk sex; MSM SW who had been raped (65.0%), had a STI (61.2%) and who self identified as female (55.6%). Significant risk factors for HIV infection common to all 3 subgroups were participation in both receptive and insertive anal intercourse, high-risk sex, and history of a STI. Perception of no or little risk, always using a condom, and being bisexual were protective.ConclusionHIV prevalence was high among MSM SW and MSM with adverse life events. Given the characteristics of the sample, HIV prevalence among MSM in Jamaica is probably in the range of 20%. The study illustrates the importance of social vulnerability in driving the HIV epidemic. Programs to empower young MSM, reduce social vulnerability and other structural barriers including stigma and discrimination against MSM are critical to reduce HIV transmission.  相似文献   

8.
Gao L  Zhou F  Li X  Yang Y  Ruan Y  Jin Q 《PloS one》2010,5(12):e15256

Background

Anal HPV infection, which contributes to the development of anal warts and anal cancer, is well known to be common among men who have sex with men (MSM), especially among those HIV positives. However, HIV and anal HPV co-infection among MSM has not been addressed in China.

Methods

A cross-sectional study was conducted in Beijing and Tianjin, China. Study participants were recruited using multiple methods with the collaboration of local volunteer organizations. Blood and anal swabs were collected for HIV-1 serological test and HPV genotyping.

Results

A total of 602 MSM were recruited and laboratory data were available for 578 of them (96.0%). HIV and anal HPV prevalence were 8.5% and 62.1%, respectively. And 48 MSM (8.3%) were found to be co-infected. The HPV genotypes identified most frequently were HPV06 (19.6%), HPV16 (13.0%), HPV52 (8.5%) and HPV11 (7.6%). Different modes of HPV genotypes distribution were observed with respect to HIV status. A strong dose-response relationship was found between HIV seropositivity and multiplicity of HPV genotypes (p<0.001), which is consistent with the observation that anal HPV infection was an independent predictor for HIV infection.

Conclusions

A high prevalence of HIV and anal HPV co-infection was observed in the MSM community in Beijing and Tianjin, China. Anal HPV infection was found to be independently associated with increased HIV seropositivity, which suggests the application of HPV vaccine might be a potential strategy to reduce the acquisition of HIV infection though controlling the prevalence of HPV.  相似文献   

9.

Background

Despite preventive efforts, HIV incidence remains high among men who have sex with men (MSM) in industrialized countries. Condoms are an important element in prevention but, given the high frequency of condom use and their imperfect effectiveness, a substantial number and proportion of HIV transmissions may occur despite condoms. We developed a model to examine this hypothesis.

Methods

We used estimates of annual prevalent and incident HIV infections for MSM in Ontario. For HIV-negative men, we applied frequencies of sexual episodes and per-contact HIV transmission risks of receptive and insertive anal sex with and without a condom and oral sex without a condom. We factored in the proportion of HIV-infected partners receiving antiretroviral therapy and its impact in reducing transmissibility. We used Monte-Carlo simulation to determine the plausible range for the proportion of HIV transmissions for each sexual practice.

Results

Among Ontario MSM in 2009, an estimated 92,963 HIV-negative men had 1,184,343 episodes of anal sex with a condom and 117,133 anal sex acts without a condom with an HIV-positive partner. Of the 693 new HIV infections, 51% were through anal sex with a condom, 33% anal sex without a condom and 16% oral sex. For anal sex with a condom, the 95% confidence limits were 17% and 77%.

Conclusions

The proportion of HIV infections related to condom failure appears substantial and higher than previously thought. That 51% of transmissions occur despite condom use may be conservative (i.e. low) since we used a relatively high estimate (87.1%) for condom effectiveness. If condom effectiveness were closer to 70%, a value estimated from a recent CDC study, the number and proportion of HIV transmissions occurring despite condom use would be much higher. Therefore, while condom use should continue to be promoted and enhanced, this alone is unlikely to stem the tide of HIV infection among MSM.  相似文献   

10.

Introduction

Previous studies have reported a possibly increasing HIV prevalence among men who have sex with men (MSM) in China. However there have been limited systematic analyses of existing surveillance data to learn the trend of HIV prevalence and factors driving the trend. The aims of this study were to examine the trend of HIV prevalence among MSM in Guangzhou and to explore the role of unprotected anal intercourse (UAI) in the trend.

Methods

Snow-ball sampling was applied in the subject recruitment for the annual serological and behavioral surveys among MSM from 2008 to 2013. Data collected in the behavioral survey include demographic information, HIV related sexual behavior with men and women, access to HIV prevention services, and symptoms of sexually transmitted infections. Chi-square test was used to analyze the trend of HIV prevalence. Multivariate logistic regression was conducted to test the factors associated with HIV infection.

Results

HIV prevalence increased significantly from 5.0% in 2008 to 11.4% in 2013 while syphilis prevalence decreased from 17.4% to 3.3% in the same period. UAI rates were high and stable in every single year, ranging from 54.5% to 62.0%. Those who were having UAI (OR = 1.80, 95% confidence interval (CI): 1.26–2.58), being migrants, having more than 10 partners, and infected with syphilis had higher risk for HIV infection.

Conclusions

HIV epidemic is expanding in Guangzhou. The persistently high UAI may have played a major role in the increasing trend of HIV prevalence. Targeted prevention program should be conducted among MSM who are migrants, low educational level, syphilis infected, or having multiple partners to encourage HIV test and change UAI behavior. The general high UAI calls for tailored intervention program to promote healthy culture and form a safe sex social norm in the MSM community.  相似文献   

11.

Purpose

Recent studies in Puerto Rico have reported an increasing incidence of anal cancer in Puerto Rican men. The objective of this study was to determine the prevalence, genotype distribution and risk factors associated with anal HPV infection among men attending an STI clinic in Puerto Rico.

Methods

We conducted a cross-sectional study among 205 men 18 years and older. A comprehensive survey was administered that included a demographic and a behavioral assessment. Separate logistic regression models were performed to determine factors associated with any, high-risk (HR), and multiple anal HPV infection.

Results

The mean age of the study sample was 38.0±13.5 years. The most common HR types were 58, 51 and 31. Overall, HR anal HPV infection was found in 53.5% of the participants. Multiple HPV types in the anal canal were found in 47.6% of the sample. A third (29.8%) of participants reported being men who had sex with men (MSM). MSM had a significantly higher prevalence of any, HR and multiple HPV infection (p-value<0.05). Separate multivariate logistic regression analyses showed that being MSM was associated with any (OR = 4.5; [95%CI: 1.9–10.7]), HR (OR = 3.4; [95%CI: 1.1–10.3) and multiple anal HPV infection (OR = 3.6; [95%CI: 1.5–9.1). HIV was marginally associated with multiple anal HPV infection in multivariate analysis (OR = 3.3; 95%CI = 1.0–11.0).

Conclusions

Anal HPV is common among sexually active men attending this STI clinic, with higher likelihood of anal HPV infection among MSM.  相似文献   

12.

Introduction

Men who have sex with men (MSM) are at high risk for HIV infection. MSM in Central Asia, however, are not adequately studied to assess their risk of HIV transmission. Methods: This study used respondent driven sampling methods to recruit 400 MSM in Almaty, the largest city in Kazakhstan, into a cross-sectional study. Participation involved a one-time interviewer-administered questionnaire and rapid HIV screening test. Prevalence data were adjusted for respondent network size and recruitment patterns. Multivariate logistic regression was used to investigate the association between HIV and selected risk factors, and unprotected anal intercourse (UAI) and selected risk factors.

Results

After respondent driven sampling (RDS) weighted analysis, 20.2% of MSM were HIV-positive, and 69.0% had unprotected sex with at least one male partner in the last 12 months. Regression analysis showed that HIV infection was associated with unprotected receptive anal sex (AOR: 2.00; 95% CI: 1.04–3.84). Having unprotected anal intercourse with male partners, a measure of HIV risk behaviors, was associated with being single (AOR: 0.38; 95% CI: 0.23–0.64); very difficult access to lubricants (AOR: 11.08; 95% CI: 4.93–24.91); STI symptoms (AOR: 3.45; 95% CI: 1.42–8.40); transactional sex (AOR: 3.21; 95% CI: 1.66–6.22); and non-injection drug use (AOR: 3.10; 95% CI: 1.51–6.36).

Conclusions

This study found a high HIV prevalence among MSM in Almaty, and a population of MSM engaging in multiple high-risk behavior in Almaty. Greater access to HIV education and prevention interventions is needed to limit the HIV epidemic among MSM in Almaty.  相似文献   

13.
ObjectiveTo evaluate current club drug use and its potential association with the transmission of HIV/STD among Changsha men who have sex with men (MSM).MethodA cross-sectional survey was conducted by using self-administered questionnaires including information regarding socio-demographics, club drug use, high-risk behaviors, and HIV/STD infections. Multiple methods including venue-based, peer referral using “snowball” techniques, and internet advertisements were used to recruit study participants.ResultsOf the 826 participants, 177 (21.4%) reported that they had used club drugs at some time before or during sex in the past six months. MSM with young age, low education level, and seeking partners through the internet or bars were the main population who used drugs. Poppers were the most common drug used among Changsha MSM. The prevalence of HIV, syphilis, and herpes simplex virus-2 were higher among drug users. There were no significant differences in unprotected sexual intercourse and condom use between drug users and non-users. Compared with non-users, risk behaviors such as group sex, multiple sex partners, and sex with foreigners were more frequent among drug users.ConclusionClub drug use is common among Changsha MSM, and is related to unsafe sex activities and HIV/STD infection. It is necessary to build novel targeted HIV prevention strategies to monitor and reduce club drug use among MSM.  相似文献   

14.
Over half of HIV infections in the United States occur among men who have sex with men (MSM). Awareness of infection is a necessary precursor to antiretroviral treatment and risk reduction among HIV-infected persons. We report data on prevalence and awareness of HIV infection among MSM in 2008 and 2011, using data from 20 cities participating in the 2008 and 2011 National HIV Behavioral Surveillance System (NHBS) among MSM. Venue-based, time-space sampling was used to recruit men for interview and HIV testing. We analyzed data for men who reported ≥1 male sex partner in the past 12 months. Participants who tested positive were considered to be aware of their infection if they reported a prior positive HIV test. We used multivariable analysis to examine differences between results from 2011 vs. 2008. HIV prevalence was 19% in 2008 and 18% in 2011 (p = 0.14). In both years, HIV prevalence was highest among older age groups, blacks, and men with lower education and income. In multivariable analysis, HIV prevalence did not change significantly from 2008 to 2011 overall (p = 0.51) or in any age or racial/ethnic category (p>0.15 in each category). Among those testing positive, a greater proportion was aware of their infection in 2011 (66%) than in 2008 (56%) (p<0.001). In both years, HIV awareness was higher for older age groups, whites, and men with higher education and income. In multivariable analysis, HIV awareness increased from 2008 to 2011 overall (p<0.001) and for all age and racial/ethnic categories (p<0.01 in each category). In both years, black MSM had the highest HIV prevalence and the lowest awareness among racial/ethnic groups. These findings suggest that HIV-positive MSM are increasingly aware of their infections.  相似文献   

15.

Background

In China, the HIV/AIDS epidemic is expanding among men who have sex with men (MSM). As independent risk factors of HIV infection, the epidemics of Chlamydia (CT) and Gonorrhea (NG) in MSM were not well studied, particular for the risk factors of these infectious. The objectives of current reported study were to understand the dynamics of HIV and other sexual transmitted infections (STIs) among MSM in Jiangsu, China, and to measure factors that correlated with STIs.

Methods

In order to gain more participants, a multisite cross-sectional study design was used in our study, by using convenience-sampling to recruit MSM in two Changzhou and Yangzhou, Jiangsu, China, between the July and October of 2009.

Results

In this comprehensive survey involving MSM in two cities of Jiangsu province of China, the prevalence of STIs of CT (6.54%), NG (3.63%), syphilis (20.34%) and HIV (11.62%) were measured. Overall, the STIs prevalence (CT, NG or syphilis) for the participants in our study was 26.39%, meanwhile, 3.4% (14 out of the 413) participants had at least two kinds of STIs. Meeting casual partners at parks, public restrooms or other public areas, having had anal sex with men in the past six months, having had STI symptoms in the past year were positively correlated with STIs positive, with adjusted ORs of 4.61(95%CI 1.03–20.75), 1.91(95%CI 1.14–3.21) and 2.36(95%CI 1.07,5.24).

Conclusion

Our study findings reiterate the fact that Chinese MSM are highly susceptible to acquiring syphilis, CT, NG and HIV, and there is an urgent need for intervention targeted towards this population. Behavioral measures should constitute an important part of the targeted intervention. Furthermore, the already implemented preventive and diagnostic services for HIV should be expanded to include syphilis CT and NG, too.  相似文献   

16.

Background

An increasing incidence of anal cancer among men, especially men who have sex with men (MSM) suggests a need to better understand anal human papillomavirus (HPV) infection among this group.

Methods

A cross-sectional study was conducted among MSM in Shenzhen, China. Blood was collected for HIV serological testing and syphilis serological screening, and anal swabs were collected for HPV genotyping. Difference of HPV prevalence between HIV seropositive and HIV seronegative MSM was assessed by chi-square test. Factors associated with anal canal HPV infection were assessed by univariate and multivariate logistic regression.

Results

A total of 408 MSM were recruited. HIV and HPV prevalence were 6.9% and 36.4%, respectively. HPV was detected in the anal canal in 71.4% of the HIV-positive MSM and in 33.8% of the HIV-negative MSM (P<0.001). Oncogenic types were seen more often in anal specimens of HIV-positive MSM than in specimens of HIV-negative MSM (P = 0.001). The HPV genotypes detected most frequently were HPV06 (8.2%), HPV16 (7.2%), HPV11 (6.4%), HPV18 (4.7%), HPV58 (4.7%), and HPV52 (4.2%).

Conclusions

In this study, HIV positive MSM had a higher burden of HPV infection, especially oncogenic HPV infection. HPV types 52 and 58 were as popular as those types designed for the currently available vaccine (HPV6, 11, 16, 18).  相似文献   

17.

Background

Men who have sex with men (MSM) are marginalized, hidden, underserved and at high risk for HIV in Nepal. We examined the association between MSM sub-populations, psychosocial health problems and support, access to prevention and non-use of condoms.

Methods

Between September-November of 2010, a cross-sectional survey on HIV-related risk behavior was performed across Nepal through snowball sampling facilitated by non-governmental organizations, recruiting 339 MSM, age 15 or older. The primary outcomes were: (a) non-use of condoms at least once in last three anal sex encounters with men and (b) non-use of condoms with women in the last encounter. The secondary outcome was participation in HIV prevention interventions in the past year.

Results

Among the 339 MSM interviewed, 78% did not use condoms at their last anal sex with another man, 35% did not use condoms in their last sex with a woman, 70% had experienced violence in the last 12 months, 61% were experiencing depression and 47% had thought of committing suicide. After adjustment for age, religion, marital status, and MSM subpopulations (bisexual, ta, meti, gay), non-use of condoms at last anal sex with a man was significantly associated with non-participation in HIV interventions, experience of physical and sexual violence, depression, repeated suicidal thoughts, small social support network and being dissatisfied with social support. Depression was marginally associated with non-use of condoms with women. The findings suggest that among MSM who reported non-use of condoms at last anal sex, the ta subgroup and those lacking family acceptance were the least likely to have participated in any preventive interventions.

Conclusions

MSM in Nepal have a prevalence of psychosocial health problems in turn associated with high risk behavior for HIV. Future HIV prevention efforts targeting MSM in Nepal should cover all MSM subpopulations and prioritize psychosocial health interventions.  相似文献   

18.

Background

Conventional epidemiological surveillance of infectious diseases is focused on characterization of incident infections and estimation of the number of prevalent infections. Advances in methods for the analysis of the population-level genetic variation of viruses can potentially provide information about donors, not just recipients, of infection. Genetic sequences from many viruses are increasingly abundant, especially HIV, which is routinely sequenced for surveillance of drug resistance mutations. We conducted a phylodynamic analysis of HIV genetic sequence data and surveillance data from a US population of men who have sex with men (MSM) and estimated incidence and transmission rates by stage of infection.

Methods and Findings

We analyzed 662 HIV-1 subtype B sequences collected between October 14, 2004, and February 24, 2012, from MSM in the Detroit metropolitan area, Michigan. These sequences were cross-referenced with a database of 30,200 patients diagnosed with HIV infection in the state of Michigan, which includes clinical information that is informative about the recency of infection at the time of diagnosis. These data were analyzed using recently developed population genetic methods that have enabled the estimation of transmission rates from the population-level genetic diversity of the virus. We found that genetic data are highly informative about HIV donors in ways that standard surveillance data are not. Genetic data are especially informative about the stage of infection of donors at the point of transmission. We estimate that 44.7% (95% CI, 42.2%–46.4%) of transmissions occur during the first year of infection.

Conclusions

In this study, almost half of transmissions occurred within the first year of HIV infection in MSM. Our conclusions may be sensitive to un-modeled intra-host evolutionary dynamics, un-modeled sexual risk behavior, and uncertainty in the stage of infected hosts at the time of sampling. The intensity of transmission during early infection may have significance for public health interventions based on early treatment of newly diagnosed individuals. Please see later in the article for the Editors'' Summary  相似文献   

19.
BACKGROUND: Population-based estimates of HIV incidence in France have revealed that men who have sex with men (MSM) are the most affected population and contribute to nearly half of new infections each year. We sought to estimate HIV incidence among sexually active MSM in Paris gay community social venues. METHODOLOGY/ PRINCIPAL FINDINGS: A cross-sectional survey was conducted in 2009 in a sample of commercial venues such as bars, saunas and backrooms. We collected a behavioural questionnaire and blood sample. Specimens were tested for HIV infection and positive specimens then tested for recent infection by the enzyme immunoassay for recent HIV-1 infection (EIA-RI). We assessed the presence of antiretroviral therapy among infected individuals to rule out treated patients in the algorithm that determined recent infection. Biomarker-based cross-sectional incidence estimates were calculated. We enrolled 886 MSM participants among which 157 (18%) tested HIV positive. In positive individuals who knew they were infected, 75% of EIA-RI positive results were due to ART. Of 157 HIV positive specimens, 15 were deemed to be recently infected. The overall HIV incidence was estimated at 3.8% person-years (py) [95%CI: 1.5-6.2]. Although differences were not significant, incidence was estimated to be 3.5% py [0.1-6.1] in men having had a negative HIV test in previous year and 4.8% py [0.1-10.6] in men having had their last HIV test more than one year before the survey, or never tested. Incidence was estimated at 4.1% py [0-8.3] in men under 35 years and 2.5% py [0-5.4] in older men. CONCLUSIONS/ SIGNIFICANCE: This is the first community-based survey to estimate HIV incidence among MSM in France. It includes ART detection and reveals a high level of HIV transmission in sexually active individuals, despite a high uptake of HIV testing. These data call for effective prevention programs targeting MSM engaged in high-risk behaviours.  相似文献   

20.

Background

Yunnan has been severely affected by HIV/AIDS in China. Recently, the reported prevalence of HIV-1 among men who have sex with men (MSM) in Yunnan was high in China. To monitor dynamic HIV-1 epidemic among Yunnan MSM, HIV-1 genetic characteristics and transmitted drug resistance (TDR) were investigated.

Methods

Blood samples from 131 newly HIV-1 diagnosed MSM were continuously collected at fixed sites from January 2010 to December 2012 in Kunming City, Yunnan Province. Partial gag, pol and env genes were sequenced. Phylogenetic, evolutionary and genotypic drug resistance analyses were performed.

Results

Multiple genotypes were identified among MSM in Kunming, including CRF01_AE (64.9%), CRF07_BC (25.2%), unique recombinant forms (URFs, 5.3%), subtype B (3.1%) and CRF08_BC (1.5%). CRF01_AE and CRF07_BC were the predominant strains. The mean of genetic distance within CRF01_AE were larger than that within CRF07_BC. The estimated introducing time of CRF01_AE in Yunnan MSM (1996.9) is earlier than that of CRF07_BC (2002.8). In this study, subtype B was first identified in Yunnan MSM. CRF08_BC seems to be the distinctive strain in Yunnan MSM, which was seldom found among MSM outside Yunnan. The proportion of URFs increased, which further contributed to genetic diversity among MSM. Strikingly, genetic relatedness was found among these strains with MSM isolates from multiple provinces, which suggested that a nationwide transmission network may exist. TDR-associated mutations were identified in 4.6% individuals. The multivariate analysis revealed that non-native MSM and divorced/widowed MSM were independently associated with a higher TDR rate.

Conclusion

This work revealed diverse HIV-1 genetics, national transmission networks and a baseline level of TDR in MSM. These findings enhance our understanding of the distribution and evolution of HIV-1 in MSM, and are valuable for developing HIV prevention strategies for MSM.  相似文献   

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