中国消除艾滋病流行面临的挑战

遏制和终结获得性免疫缺陷综合征(艾滋病)(acquired immune deficiency syndrome, AIDS)是《“健康中国2030”规划纲要》的重要组成部分和联合国2030年可持续发展目标之一。虽然中国在应对人类免疫缺陷病毒(human immunodeficiency virus, HIV)/AIDS流行方面确实取得了实质性进展,但终结AIDS流行愿景仍面临重重挑战。在筛查和诊断方面:HIV的扩大筛查和早期发现仍是中国应对HIV的关键;在治疗方面:HIV感染者的免费抗病毒治疗策略存在局限性,HIV感染者拒绝或中途退出治疗的状况时有发生,AIDS难以治愈等,解决这些问题困难重重;在预防方面:预防药物推广存在难度,疫苗研究仍未取得突破;在社会支持方面:对HIV/AIDS患者的歧视依然存在,非政府组织的参与度存在局限性。因此,针对男男性行为者(men who have sex with men, MSM)、吸毒者、老年人等关键易感人群及流行率较高的特定地区设计和制定包括诊断、治疗、预防及社会支持在内的HIV感染防治综合策略,对中国消除AIDS流行具有重要意义。     

GBV-C/HIV共感染对AIDS疾病进程和HIV病毒复制的影响

近年来,一些研究发现,GBV-C/HIV共感染可延缓HIV感染疾病的进程,然而也有一些研究得出不同的结论.本研究收集我国安徽省阜阳市HIV血清学阳性的既往献血员血浆标本,对其进行GBV-C感染的检测,研究GBV-C/HIV共感染与HIV病毒载量和CD4 T淋巴细胞绝对计数的关系.用RT-PCR和酶联免疫法检测,在203人中检出GBV-C感染52例,显示该人群GBV-C的感染率为25.6%,男性感染者(35例,67.3%)高于女性感染者(17例,32.7%).分析发现,GBV-C感染与未感染两组患者的CD4 T淋巴细胞绝对计数和HIV病毒载量数据均无统计学差异.本研究中的HIV-1感染者均未接受ART治疗,因而排除了治疗对疾病进展的影响.研究结果显示,在HIV-1感染晚期的献血人群,GBV-C/HIV共感染对CD4细胞和病毒复制水平无显著影响.由于本研究对象中无HIV-1早期感染者,因而不能判断GBV-C在HIV-1感染的早期对疾病进展有无影响.     

人类免疫缺陷病毒与深部真菌感染

人类免疫缺陷病毒（HIV）感染的发病率与致死率很高,已成为人类健康的一大威胁,其中约50％的HIV感染者最终因侵袭性真菌病而死亡。高效抗反转录病毒治疗（HAART）的应用大大降低了 HIV感染者深部真菌病的发生率。因此,深入研究HIV与深部真菌病的关系,对预防、诊断和治疗HIV感染者深部真菌病具有十分重要的意义。本文归纳了HIV感染者深部真菌病的流行病学调查、诊断与治疗进展,有助于临床医师预防和诊治HIV感染者深部真菌病,也为将来新型抗真菌药物的研发提供了思路和方向。     

矿物质在HIV感染/艾滋病患者营养干预中的作用

目的：了解矿物质在人类免疫缺陷病毒（HIV）感染/艾滋病营养干预中的作用。方法：通过检索查阅国内（万方、中国知网、维普等，1997—2020年）和国外（Cochrane library、Pubmed、EMbase等，2002—2020年）的相关文献，纳入8篇论文形成证据体，对其进行评价（参照WHO推荐的证据评价方案及标准）。结果与结论：HIV感染/艾滋病患者易出现一种或多种矿物质不足或缺乏的情况，部分矿物质补充能够改善HIV感染/艾滋病患者的营养状况，其中的硒补充可能延缓艾滋病疾病进展、改善患者生存以及带来额外的健康收益，锌补充可能延缓HIV感染/艾滋病患者的疾病进展、降低腹泻的发生率以及带来额外的健康收益。     

维生素在HIV感染/艾滋病患者营养干预中的作用

目的：了解维生素在人类免疫缺陷病毒(HIV)感染/艾滋病患者营养干预中的作用。方法：通过检索查阅国内（万方、中国知网、维普等,1997—2020年）和国外（Cochrane Library、PubMed、Embase等,2002—2020年）的相关文献,共纳入41篇学术论文进行证据体评价（参照WHO推荐的证据评价方案及标准）。结果：HIV感染/艾滋病患者易出现一种或多种维生素不足或缺乏的情况,维生素补充能够改善HIV感染/艾滋病患者的营养状况。维生素A的补充可能降低HIV感染/艾滋病患者的死亡风险、延缓疾病进展以及带来额外的健康收益,但会增加HIV垂直传播风险;烟酸补充可以改善HIV感染/艾滋病患者的血脂水平;补充维生素C、维生素E可以降低HIV感染/艾滋病患者的氧化应激水平;补充维生素D可改善HIV感染/艾滋病患者的骨骼健康,降低冠心病、结核以及肝纤维化的发生风险。结论：复合维生素补充（包括矿物质）可能延缓HIV感染/艾滋病患者的疾病进展以及带来额外的健康收益。     

PLoS Comput Biol:患者和HIV遗传差异共同决定着HIV的感染进展

正根据一项新的研究,在HIV感染者之间观察到的疾病进展率差异当中,大约三分之一的差异是由HIV遗传差异和患者遗传差异一起导致的。这些发现提示着患者遗传差异通过触发HIV病毒基因组发生突变而影响疾病进展。相关研究结果发表在PLoS Computational Biology期刊上。HIV感染者经历着不同的疾病进展率。在具有更高病毒载量的HIV感染者体内,HIV进展得更快。HIV病毒载量指的是在一名感染者的血液     

江苏省300例艾滋病人群联合检测 HCV、TP、HIV的结果分析

摘要 目的：探究江苏省2017年至2019年度艾滋病哨点监测人群丙型肝炎病毒（Hepatitis C virus,HCV）、梅毒螺旋体（Treponema Pallidum,TP）以及人类免疫缺陷病毒（Treponema Pallidum,HIV）感染状况,以期为制定对应的疾患干预手段提供临床数据支撑。方法：严格按照《全国艾滋病哨点监测实施方案操作手册（2012版）》对入组的900例个体开展相关问卷调查,并对入组对象进行HCV、TP以及HIV感染血清学检测,分别统计3年总体感染情况、年度感染情况、不同年龄段人群感染情况以及合并感染情况。结果：（1）性工作者HCV、TP以及HIV感染率分别为3.00 %、4.00 %和9.00 %,吸毒人群感染率分别为13.00 %、73.00 %和13.00 %,孕产妇感染率分别为1.00 %、0.67 %和1.33 %,比较显示,吸毒人群HCV、TP以及HIV感染率明显高于其余两类人群（P<0.05）;（2）就各年度不同人群HCV、TP以及HIV感染率开展年度横向比较显示,不同年度不同人群的HCV、TP以及HIV感染率差异无统计学意义（P>0.05）;（3）针对不同年龄段不同人群的HCV、TP以及HIV感染率开展比较显示,吸毒人群中≥50岁HCV和HIV感染率明显高于其他年龄段（P<0.05）,性工作者中18~20岁HIV感染率明显高于其他年龄段（P<0.05）,其余差异无统计学意义（P>0.05）;（4）合并感染情况分析显示合并TP以及HIV感染率要高于其他合并感染。结论：吸毒人群是江苏省HCV、TP以及HIV感染高发群体,以≥50岁年龄段感染率最高,总体来看HCV、TP以及HIV感染率呈现逐年降低趋势,但仍应该加强对上述疾患的防控工作。     

77例人类免疫缺陷病毒感染者临床特征分析

目的 分析人类免疫缺陷病毒(HIV)感染者的临床特点及其意义。方法 用微粒酶免疫试验和蛋白质印迹法对HIV感染者的血清进行HIV抗体初筛和确认,并对感染者的流行病学、机会性感染及免疫学特点进行分析。结果 在1998~2006年期间,我院共发现77例HIV感染者,其中上海户籍患者占了50.7%,男、女比例为2.85∶1,年龄以30~49岁为主,传播途径中以性传播最常见(40.3%)。早期症状常被忽略,以消化道及肺部真菌、假单胞菌感染,性传播疾病,病毒性肝炎,皮损等就诊于各科室。多重或多部位的机会性感染可见于大多数临床已发病患者。结论 HIV感染的及时诊断,对感染者的治疗、机会性感染的预防以及减少传播具有重要的意义。     

《核酸研究》：新突变体可选择杀伤HIV感染细胞

艾滋病病毒（HIV）存在潜藏机制可以长期潜伏在细胞中而逃逸宿主免疫系统的攻击,目前已上市的抗HIV药物均不能选择性地杀伤感染细胞而根除病毒。新的研究思路对开发新型抗HIV药物显得非常重要,研究具有选择性地杀伤HIV感染细胞而保护正常细胞不受伤害的抗艾滋病药物是极有前景的方向。     

031高效抗反转录治疗使人类免疫缺陷病毒 -丙型肝炎病毒双重感染者病死率高于单纯人类免疫缺陷病毒感染

高效抗反转录治疗（HAART）使人类免疫缺陷病毒（HIV）感染者的病死率大大降低,但对于同时感染丙型肝炎病毒（HCV）的患者,其治疗效果需要进一步评价。HIV感染者合并感染HCV的比例很高,为10％～40％,主要是因为HIV与HCV有共同的传播途径,如吸毒或接受不洁血制品。HCV有较长的潜伏期,所以HIV患者在接受HAART的早期可能没有考虑到肝脏疾病。     

Gaining greater insight into HCV emergence in HIV-infected men who have sex with men: the HEPAIG Study

Objectives

The HEPAIG study was conducted to better understand Hepatitis C virus (HCV) transmission among human immuno-deficiency (HIV)-infected men who have sex with men (MSM) and assess incidence of HCV infection among this population in France.

Methods and Results

Acute HCV infection defined by anti-HCV or HCV ribonucleic acid (RNA) positivity within one year of documented anti-HCV negativity was notified among HIV-infected MSM followed up in HIV/AIDS clinics from a nationwide sampling frame. HIV and HCV infection characteristics, HCV potential exposures and sexual behaviour were collected by the physicians and via self-administered questionnaires. Phylogenetic analysis of the HCV-NS5B region was conducted.HCV incidence was 48/10 000 [95% Confidence Interval (CI):43–54] and 36/10 000 [95% CI: 30–42] in 2006 and 2007, respectively. Among the 80 men enrolled (median age: 40 years), 55% were HIV-diagnosed before 2000, 56% had at least one sexually transmitted infection in the year before HCV diagnosis; 55% were HCV-infected with genotype 4 (15 men in one 4d-cluster), 32.5% with genotype 1 (three 1a-clusters); five men were HCV re-infected; in the six-month preceding HCV diagnosis, 92% reported having casual sexual partners sought online (75.5%) and at sex venues (79%), unprotected anal sex (90%) and fisting (65%); using recreational drugs (62%) and bleeding during sex (55%).

Conclusions

This study emphasizes the role of multiple unprotected sexual practices and recreational drugs use during sex in the HCV emergence in HIV-infected MSM. It becomes essential to adapt prevention strategies and inform HIV-infected MSM with recent acute HCV infection on risk of re-infection and on risk-reduction strategies.     

Anal HPV infection in HIV-positive men who have sex with men from China

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.     

A mathematical model of comprehensive test-and-treat services and HIV incidence among men who have sex with men in the United States

Background

Early diagnosis and treatment of HIV infection and suppression of viral load are potentially powerful interventions for reducing HIV incidence. A test-and-treat strategy may have long-term effects on the epidemic among urban men who have sex with men (MSM) in the United States and may achieve the 5-year goals of the 2010 National AIDS Strategy that include: 1) lowering to 25% the annual number of new infections, 2) reducing by 30% the HIV transmission rate, 3) increasing to 90% the proportion of persons living with HIV infection who know their HIV status, 4) increasing to 85% the proportion of newly diagnosed patients linked to clinical care, and 5) increasing by 20% the proportion of HIV-infected MSM with an undetectable HIV RNA viral load.

Methods and Findings

We constructed a dynamic compartmental model among MSM in an urban population (based on New York City) that projects new HIV infections over time. We compared the cumulative number of HIV infections in 20 years, assuming current annual testing rate and treatment practices, with new infections after improvements in the annual HIV testing rate, notification of test results, linkage to care, initiation of antiretroviral therapy (ART) and viral load suppression. We also assessed whether five of the national HIV prevention goals could be met by the year 2015. Over a 20-year period, improvements in test-and-treat practice decreased the cumulative number of new infections by a predicted 39.3% to 69.1% in the urban population based on New York City. Institution of intermediate improvements in services would be predicted to meet at least four of the five goals of the National HIV/AIDS Strategy by the 2015 target.

Conclusions

Improving the five components of a test-and-treat strategy could substantially reduce HIV incidence among urban MSM, and meet most of the five goals of the National HIV/AIDS Strategy.     

Biomarker-based HIV incidence in a community sample of men who have sex with men in Paris, France

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.     

Higher viral load and genetic diversity of HIV‐1 in seminal compartments than in blood of seven Chinese men who have sex with men and have early HIV‐1 infection

To date, there have been no reports characterizing HIV‐1 in the semen of Chinese men who have sex with men (MSM) with early infection. In this study, genetic diversity and viral load of HIV‐1 in the seminal compartments and blood of Chinese MSM with early HIV‐1 infection were examined. Viral load and genetic diversity of HIV‐1 in paired samples of semen and blood were analyzed in seven MSM with early HIV‐1 infection. HIV‐1 RNA and DNA were quantitated by real‐time PCR assays. Through sequencing the C2‐V5 region of the HIV‐1 env gene, the HIV‐1 genotype and genetic diversity based on V3 loop amino acid sequences were determined by using Geno2pheno and PSSM programs co‐receptor usage. It was found that there was more HIV‐1 RNA in seminal plasma than in blood plasma and total, and more 2‐LTR circular and integrated HIV‐1 DNA in seminal cells than in peripheral blood mononuclear cells from all seven patients with early HIV‐infection. There was also greater HIV‐1 genetic diversity in seminal than in blood compartments. HIV‐1 in plasma displayed higher genetic diversity than in cells from the blood and semen. In addition, V3 loop central motifs, which present some key neutralizing antibody epitopes, varied between blood and semen. Thus, virological characteristics in semen may be more representative when evaluating risk of transmission in persons with early HIV infection.

     

Resurgence of HIV Infection among Men Who Have Sex with Men in Switzerland: Mathematical Modelling Study

Background

New HIV infections in men who have sex with men (MSM) have increased in Switzerland since 2000 despite combination antiretroviral therapy (cART). The objectives of this mathematical modelling study were: to describe the dynamics of the HIV epidemic in MSM in Switzerland using national data; to explore the effects of hypothetical prevention scenarios; and to conduct a multivariate sensitivity analysis.

Methodology/Principal Findings

The model describes HIV transmission, progression and the effects of cART using differential equations. The model was fitted to Swiss HIV and AIDS surveillance data and twelve unknown parameters were estimated. Predicted numbers of diagnosed HIV infections and AIDS cases fitted the observed data well. By the end of 2010, an estimated 13.5% (95% CI 12.5, 14.6%) of all HIV-infected MSM were undiagnosed and accounted for 81.8% (95% CI 81.1, 82.4%) of new HIV infections. The transmission rate was at its lowest from 1995–1999, with a nadir of 46 incident HIV infections in 1999, but increased from 2000. The estimated number of new infections continued to increase to more than 250 in 2010, although the reproduction number was still below the epidemic threshold. Prevention scenarios included temporary reductions in risk behaviour, annual test and treat, and reduction in risk behaviour to levels observed earlier in the epidemic. These led to predicted reductions in new infections from 2 to 26% by 2020. Parameters related to disease progression and relative infectiousness at different HIV stages had the greatest influence on estimates of the net transmission rate.

Conclusions/Significance

The model outputs suggest that the increase in HIV transmission amongst MSM in Switzerland is the result of continuing risky sexual behaviour, particularly by those unaware of their infection status. Long term reductions in the incidence of HIV infection in MSM in Switzerland will require increased and sustained uptake of effective interventions.     

HIV and syphilis co-infection increasing among men who have sex with men in China: a systematic review and meta-analysis

Background

This study aims to estimate the magnitude and changing trends of HIV, syphilis and HIV-syphilis co-infections among men who have sex with men (MSM) in China during 2003–2008 through a systematic review of published literature.

Methodology/Principal Findings

Chinese and English literatures were searched for studies reporting HIV and syphilis prevalence among MSM from 2003 to 2008. The prevalence estimates were summarized and analysed by meta-analyses. Meta-regression was used to identify the potential factors that are associated with high heterogeneities in meta-analysis. Seventy-one eligible articles were selected in this review (17 in English and 54 in Chinese). Nationally, HIV prevalence among MSM increased from 1.3% during 2003–2004 to 2.4% during 2005–2006 and to 4.7% during 2007–2008. Syphilis prevalence increased from 6.8% during 2003–2004 to 10.4% during 2005–2006 and to 13.5% during 2007–2008. HIV-syphilis co-infection increased from 1.4% during 2005–2006 to 2.7% during 2007–2008. Study locations and study period are the two major contributors of heterogeneities of both HIV and syphilis prevalence among Chinese MSM.

Conclusions/Significance

There have been significant increases in HIV and syphilis prevalence among MSM in China. Scale-up of HIV and syphilis screening and implementation of effective public health intervention programs should target MSM to prevent further spread of HIV and syphilis infection.     

Screening acute HIV infections among Chinese men who have sex with men from voluntary counseling & testing centers

Background

Recent studies have shown the public health importance of identifying acute HIV infection (AHI) in the men who have sex with men (MSM) of China, which has a much higher risk of HIV transmission. However, cost-utility analyses to guide policy around AHI screening are lacking.

Methodology/Principal Findings

An open prospective cohort was recruited among MSM living in Liaoning Province, Northeast China. Blood samples and epidemiological information were collected every 10 weeks. Third-generation ELISA and rapid test were used for HIV antibody screening, western blot assay (WB) served for assay validation. Antibody negative specimens were tested with 24 mini-pool nucleic acid amplification testing (NAAT). Specimens with positive ELISA but negative or indeterminate WB results were tested with NAAT individually without mixing. A cost-utility analysis of NAAT screening was assessed. Among the 5,344 follow-up visits of 1,765 MSM in 22 months, HIV antibody tests detected 114 HIV chronic infections, 24 seroconverters and 21 antibody indeterminate cases. 29 acute HIV infections were detected with NAAT from 21 antibody indeterminate and 1,606 antibody negative cases. The HIV-1 prevalence and incidence density were 6.6% (95% CI: 5.5–7.9) and 7.1 (95% CI: 5.4–9.2)/100 person-years, respectively. With pooled NAAT and individual NAAT strategy, the cost of an HIV transmission averted was $1,480. The addition of NAAT after HIV antibody tests had a cost-utility ratio of $3,366 per gained quality-adjusted life year (QALY). The input-output ratio of NAAT was about 1∶16.9.

Conclusions/Significance

The HIV infections among MSM continue to rise at alarming rates. Despite the rising cost, adding pooled NAAT to the HIV antibody screening significantly increases the identification of acute HIV infections in MSM. Early treatment and target-oriented publicity and education programs can be strengthened to decrease the risk of HIV transmission and to save medical resources in the long run.     

A baseline epidemiological study of the co-infection of enteric protozoans with human immunodeficiency virus among men who have sex with men from Northeast China

BackgroundHuman immunodeficiency virus (HIV) and enteric parasite co-infection not only aggravates the clinical symptoms of parasites but also accelerates acquired immunodeficiency syndrome (AIDS) progression. However, co-infection research on men who have sex with men (MSM), the predominant high-risk population of HIV/AIDS in China, is still limited. In this study, we investigated the epidemiology of enteric parasites, risk factors, and associations with clinical significance in an MSM HIV/AIDS population in Heilongjiang Province, northeast China.MethodsWe recruited 308 MSMs HIV/AIDS patients and 199 HIV-negative individuals in two designated AIDS hospitals in Heilongjiang between April 2016 and July 2017. Fresh stool samples were collected. DNA extraction, molecular identification, and genotyping of Cryptosporidium species, Entamoeba histolytica, Cyclospora cayetanensis, Enterocytozoon bieneusi, and Blastocystis hominis were performed. Fourteen diarrhea-related pathogens were examined to exclude the influence of other bacterial pathogens on diarrhea incidence.Results31.5% of MSM HIV/AIDS participants were infected with at least one parasite species, a significantly higher proportion than that found in the HIV-negative individuals (2.5%). E. bieneusi presented the highest prevalence, followed by B. hominis, E. histolytica, Cryptosporidium spp., and C. cayetanensis. Warm seasons were the risk factor for parasitic infections in this population [odds ratio (OR) = 2.6, 95% CI: 1.47–4.57]. In addition, these individuals showed a higher proportion (35.8%) of present diarrhea (PD) compared with men who have sex with women (MSW) with HIV/AIDS (16.7%). The infection proportions of both Cryptosporidium spp. and E. histolytica were significantly higher in the PD. E. bieneusi infection was more prevalent in the historic diarrhea (HD) group. CD4⁺ T cell counts in the MSM patients with the above three parasites were significantly lower. New species and genotypes were found, and MSM patients had a wider range of species or genotypes.ConclusionsEnteric parasitic infection was prevalent in the MSM HIV/AIDS population, especially in patients with present diarrhea during warm seasons. E. histolytica and B. hominis should also be considered high-risk parasites for opportunistic infections in AIDS patients in addition to Cryptosporidium spp.     

The HIV epidemic among men who have sex with men—behaviour beats science

More than three decades after the emergence of HIV/AIDS, more than 30 million people worldwide still live with the disease. In the West, those most at risk are men who have sex with men owing to a combination of social factors and, ironically, improved healthcare.The acquired immune deficiency syndrome (AIDS) pandemic that started more than 30 years ago remains one of the greatest public-health concerns worldwide: in 2009, it was estimated that 33.3 million individuals were infected with human immunodeficiency virus (HIV), with 2.6 million new infections globally (see graphic; [1]). Even in the affluent countries of North America, Australia, New Zealand and Western and Central Europe, the numbers of people infected with HIV have grown over the past two decades. Although the availability of efficient diagnostics and highly active antiretroviral therapy (HAART) have drastically improved life expectancy and quality of life—at least in those parts of the world where both are available and affordable—HAART does not cure the disease. Moreover, despite massive research efforts, there is no efficient vaccine on the market to protect against infection with HIV.Given the lack of either a vaccine or a cure, the main public-health intervention to halt the pandemic is to prevent viral transmission in the first placeGiven the lack of either a vaccine or a cure, the main public-health intervention to halt the pandemic is to prevent viral transmission in the first place. In fact, the transmission of HIV is not as efficient as other, more resistant blood-borne viruses such as hepatitis B and hepatitis C viruses (HBV and HCV), and it requires direct contact of blood or semen from an infected person with the blood system of the exposed person. This feature puts certain groups at greater risk of transmission: heterosexuals with many sexual partners, including sex workers, men who have sex with men (MSM—a technical term used by health professionals to avoid forcing individuals to define themselves in a specific sexuality), people who inject drugs, newborns of HIV-infected mothers, blood recipients and healthcare workers. Yet, the risk of infection differs for each of these groups. There is also a geographical dimension to the risk, as different parts of the world have unique epidemiological characteristics, reflecting biological, behavioural and socio-economic factors. In many parts of Africa and Asia, for example, the most susceptible groups are heterosexuals and sex workers; in Eastern Europe, people who inject drugs are mainly affected; and in western countries, the most vulnerable population are MSM, followed by heterosexual migrants from areas where HIV is endemic [2].

Science & Society Series on Sex and Science

Sex is the greatest invention of all time: not only has sexual reproduction facilitated the evolution of higher life forms, it has had a profound influence on human history, culture and society. This series explores our attempts to understand the influence of sex in the natural world, and the biological, medical and cultural aspects of sexual reproduction, gender and sexual pleasure.Public-health programmes intended to prevent the transmission of HIV therefore have to address these groups individually. Such measures require education and the involvement of at-risk populations, and recommendations must be based on a thorough understanding of the social, economic and other factors that determine disease risk among certain groups of people. For instance, one of the most efficient measures to decrease the risk of HIV infection among people who inject drugs is to offer clean syringes and needles,and safe places to use them. One of the most efficient ways to prevent HIV transmission during sexual intercourse is the use of condoms. But, the answers are not always as simple; human behaviour is complex and even irrational at times. This paper outlines the main causes of the HIV epidemic among MSM in western countries, highlights specific behavioural factors that increase exposure to HIV and discusses how these can be addressed in public-health programmes.AIDS was first identified and described in the USA in June 1981 [3]. Following reports from Los Angeles and New York City about clusters of otherwise healthy Caucasian MSM who developed Kaposi''s sarcoma and fatal Pneumocystis carinii (jirovecii) pneumonia, the US Centers for Disease Control and Prevention (CDC) conducted an epidemiological investigation and identified a man they referred to as ‘patient zero'': a flight attendant working for Air Canada named Gaëtan Dugas, who had numerous male sexual partners in North America. Dugas might not have been the first person who was infected with HIV, but the first one who was identified with the disease.​disease.Open in a separate windowSee full size illustration: http://staging-www.nature.com/embor/journal/v13/n11/full/embor2012152i1.htmlIt was a combination of a general liberal attitude towards sex that was prevalent among MSM, unprotected anal sex and having multiple sexual partners that allowed HIV to spread quickly among the gay community in the early 1980s. Owing to the overwhelming impact on MSM in the early years of the AIDS epidemic—when many MSM saw close friends, partners and lovers die—gay communities adopted a range of practices to reduce the risk of infection successfully by changing sexual behaviours. Regretfully, these achievements did not last; many other developed countries also recorded a resurgence in the number of MSM newly diagnosed with HIV/AIDS since the mid-1990s [4]. The main reason for the re-emergence of the disease was the come-back of risky sexual behaviours, triggered by wider social and cultural changes, greater social acceptance for gay men and, somehow unpredictably, the introduction of more efficient drugs [5].The most important risk factor for exposure to HIV among MSM remains sexual practices. As the rectal mucosa is more fragile than the vaginal or oral, anal sex increases the risk for transmitting HIV and other sexually transmitted infections (STIs). The frequency of risky sexual practices between MSM seems to be increasing [6], which would go some way to explaining the resurgence of AIDS.Another main factor for the resurgence of AIDS among the gay communities in western countries is, ironically, the efficiency of HAARTIn addition, gay communities have a relatively liberal attitude towards sex and partnership. The way they form partnerships may differ from many heterosexuals: the sexual contact is more instantaneous and spontaneous, and sexual intercourse may take place early in a relationship [7]. Relationships between some MSM may be more flexible, and concurrent sex with casual partners during a relationship is generally more tolerable [8,9]. Concomitancy and age-mixing of sexual partners has a strong influence on the dynamic of HIV transmission if an infected man is unaware of his infection owing to the asymptomatic nature during the first years of HIV infection, or because he has not been tested for HIV [10]. Early sexual debut is another reason for greater exposure to HIV, as MSM would have more partners during their lifetime.Social changes have also played a role in increasing the HIV transmission rate among MSM. Since the 1990s, homosexuality and gay lifestyle have become much more accepted in many western societies. This increasing tolerance and acceptance has enabled many MSM ‘to get out of the closet'', that is to disclose their sexual orientation and have fulfilling lives. It has also encouraged entrepreneurs to tap into this customer base by offering services and establishments specifically for MSM including cafés, bars, clubs, restaurants, hotels and bath houses, all specifically intended for the purpose of meeting other men. This sexually liberal climate, along with the venues to meet other gay men, has amplified the risk of having sex with an HIV-infected partner.Similarly, the rise of internet-dating sites has increased the ease with which new partners can be found. New sexual practices and behavioural norms are quickly diffused between cultures, with possible international importing of HIV and other STIs. The internet, which is affordable, immediate and discrete, has become the most popular way of searching for other MSM. Most gay-related internet sites are free and guarantee anonymity until participants find the preferred fit and disclose their personal details or picture. The discrete nature of the web also allows MSM who are still ‘in the closet'' or ‘on the down low'' to search for sexual partners. This electronic meeting place might modify the sexual risk, as it exposes users to a diverse pool of men and increases their ability to search and negotiate for sexual practices [11]. The anonymity also allows MSM to search explicitly for unprotected anal sex [12]. MSM who originate from low-resource countries and migrate to developed countries might not be familiar with the risk of unprotected sex and may also be excited about the sizeable and versatile MSM community in the hosting country [12]. A combination of insufficient knowledge about HIV/AIDS, coupled with their interest in experiencing gay life, may increase the risk for those migrants to become infected with HIV.…the chances that an HIV-negative MSM finds himself engaged in sexual contact with an HIV-infected partner are higher than 15 years agoCorresponding with the increased number of sexual partners and the greater risk during sexual intercourse, MSM are also exposed to other STIs, especially if they are already infected with HIV. Increasing incidence of syphilis, as well as outbreaks of primary and secondary syphilis among MSM, has been reported during the past decade from developed countries [13,14]. Primary syphilis might manifest in a ‘chancer''—a sore—which is a possible port of entry for HIV. Additionally, the immunological reaction to STIs includes the migration of macrophages and lymphocytes to the affected organs. These cells are also the target of HIV, and thus one STI increases the chances of infection with further STIs or HIV. Over the past years, several outbreaks of lymphogranuloma venereum (an uncommon STI), presenting proctitis (inflammation of the rectum), and genital ulcers with inguinal adenopathy (inflammation of the lymph nodes in the groin) have been reported [15]. The asymptomatic nature of some STIs, along with the limited success of the risk-reduction strategies practiced by MSM, might explain the increased incidence of STIs among gay men [16,17]. Among HIV-infected individuals, genital infections with common STI pathogens have been associated with increased HIV viral load in semen, thus negating the benefit of HAART [18].Another important factor for the resurgence of AIDS among the gay communities in western countries is, ironically, the efficiency of HAART, which has converted AIDS from a death sentence into a manageable chronic medical condition. As the perceived threat of HIV/AIDS diminishes and direct experience with death disappears, some MSM may be more inclined to take higher risks. Before the introduction of HAART in the mid-1990s, most MSM had direct experience of the devastating effects of HIV/AIDS on friends and loved ones. It is important to note that HAART reduces the viral load in HIV-infected persons to undetectable levels in the blood and thereby decreases the risk of infecting partners. However, studies have documented the persistence of HIV virions and infected cells in semen of HIV-infected MSM treated with HAART [19]. Most physicians, therefore, do not recommend unprotected sex for HAART-treated HIV/AIDS patients, although the risk of HIV transmission has been significantly reduced.…public-health measures to reduce the prevalence of HIV among MSM should focus on the behavioural and psychosocial factors that increase the risk of infectionAs such, HAART has profoundly changed the impact of HIV/AIDS: people who live with HIV/AIDS who adhere to their drug regimen are usually asymptomatic and seem healthy. The non-fatal prognosis for AIDS, the large communities of HIV-infected MSM who live apparently healthy lives and the greater social acceptability of the disease have together reduced the perceived threat of HIV/AIDS.The success of HAART has affected sexual behaviour, a phenomenon called ‘AIDS optimism''. First, as HIV-infected MSM feel healthy and their sex-drive is preserved, they have a normal sex life and seek sexual partners, similarly to HIV-negative MSM. Second, before HAART and during its introduction in the 1990s, people living with HIV/AIDS could be recognized either by their cachectic posture or by the lipodystrophic features of their cheekbones and limbs due to loss of subdermal fat—a side-effect of the first generation of protease inhibitors. HIV-negative MSM could therefore decline sexual contact or insist on safer sex practices. However, modern HAART has diminished side-effects and HIV-infected men are usually unrecognizable. MSM may wrongly consider their sexual partners to be HIV-negative and might have unprotected sex. Third, some MSM may be aware of the availability of post-exposure prophylaxis as an additional use of ART, and might have unprotected sex then request the treatment, which is available up to 72 hours after sex [20]. These men may not be aware that post-exposure treatment has not been proven to be efficient in humans in randomized clinical trials. Finally, young MSM, who have not witnessed the devastation of AIDS, may no longer feel threatened by the disease and might engage in unprotected sex. The advanced manageability of HIV, as portrayed in the media and advertisements sponsored by the pharmaceutical industry, may further disinhibit their sexual behaviour.Moreover, the success of HAART and decades of public-health recommendations to practice safe sex may have led to ‘AIDS fatigue''. Some MSM may become desensitized to safe-sex messages and might develop a negative emotional response to HIV issues. As the number of newly diagnosed HIV-positive MSM is increasing, some will also remain unaware of their infection and may ignore safe-sex practices. Thus, the chances that an HIV-negative MSM finds himself engaged in sexual contact with an HIV-infected partner are higher than 15 years ago. Some public-health professionals argue that the uptake of HIV tests among MSM has more to do with the increased acceptance of their lifestyle than an increasing infection rate; thus the high HIV rates recorded are no more than epidemiological fallacy. However, even if this assumption is true, it neither explains the rapid dynamic of HIV transmission among MSM communities, nor the increased syphilis infection rates. Additionally, ART-resistant strains of HIV have emerged, which complicates treatment and prolongs the transmission period. The prevalence of primary or transmitted drug-resistant HIV strains in North America and Western Europe is as high as 26% [21].…it crucially requires the involvement and engagement of the gay community themselves to maintain effective and acceptable interventionsDrug abuse is another relevant risk factor. Even if the percentage of intravenous drug users among MSM may not differ compared with the percentage among heterosexuals, it creates a twofold risk of acquiring HIV: by blood-to-blood transmission when sharing needles and syringes, and by semen-to-blood exposure when having sex. Some males who inject drugs may also engage in sex with other males, although they are heterosexuals, to finance their addiction.MSM are generally aware of their risk of acquiring HIV and of the importance of condom use. Yet, they have developed alternative strategies to prevent possible HIV exposure that involve evaluating their partners and the environment in which they meet more carefully, and then taking calculated risks [22]. One such strategy used is called ‘negotiated safety'', in which both men disclose to each other their HIV status before they have sexual intercourse and may decide to perform unprotected anal sex if they are both negative. The efficacy of this strategy depends on the time at which they were tested, their honesty and being safe if performing sex outside the primary sexual relationship. The second strategy is ‘sero-sorting'', when MSM restrict unprotected anal intercourse only to partners they believe to be concordant [23]. MSM negotiate and try to identify signs that might indicate that a partner could be HIV-positive, such as special physical features—being cachectic or lypodystrophic—the venue and context in which they meet, and when visiting the home of a partner, taking a quick look in their drawers or in the bathroom closet to search for HAART tablets (‘sero-guessing''). Another strategy is called ‘strategic positioning'', which is the use of sero-status to determine sexual roles in which MSM may perform only oral sex or take the active role in anal sex. However, these risk reduction strategies, widely used by MSM, offer only limited protection from HIV [24].The recommended use of condoms during anal sex can fall by the wayside after recreational drug use. Drugs such as alcohol and methamphetamine, which are commonly used at clubs, discos and other venues, lower social barriers and increase sociability. MSM using such drugs are therefore more inclined to have sex with an unknown partner and might not use a condom, as their judgment is impaired. This risky combination of drug use during sexual contact is called ‘party and play'' on internet sites for MSM who are searching for a partner [25].The result is that in the post-HAART era, MSM still remain the group most at risk of acquiring HIV, with substantial evidence for continuing HIV transmission. It has been estimated that more than 40% of HIV-positive young MSM are involved in risky sexual behaviour, despite their awareness of their infection [26,27]. Behavioural, emotional, psychological, environmental and epidemiological factors all act synergistically to increase risk-taking when it comes to sexual practices, thus exacerbating HIV incidence in MSM. These factors might be even more dominant among HIV-positive MSM, driving them to perform unprotected anal sex. They face specific psychosocial factors such as the need to be loved and cared for, a different meaning of sex as an emotional connection and a decreased desire for intimacy after their diagnosis, owing to mixed feelings of shame and guilt [24].By contrast, HIV-infected MSM who receive HAART and achieve undetectable viral load in their blood usually reduce the risk of transmitting the virus to their sexual contacts, and probably engage less in risky sexual behaviour than those who are not on ART [28]. One explanation is that they frequent HIV clinics more often and are therefore more aware of the need to use condoms, and receive positive self-care advice. Some studies have shown that many HIV-positive men are also engaged in both sero-sorting and strategic positioning, probably to avoid HIV transmission to members of their social and sexual networks [29].…the success of HAART and decades of public-health recommendations to practice safe sex might have led to ‘AIDS fatigue''Some HIV-infected MSM therefore prefer to contact sero-concordant HIV-positive partners to experience unprotected anal intercourse, free from the worry of infecting a negative partner, or the embarrassment of having to disclose their HIV status to a negative partner, exposing themselves to the stigma attached to HIV. These perceived benefits seem to outweigh the perceived risks of contracting another strain of HIV, potentially drug-resistant, or STIs.Lacking an efficient vaccine or cure for AIDS, public-health measures to reduce the prevalence of HIV among MSM should focus on the behavioural and psychosocial factors that increase the risk of infection. Effectively, this means educational and outreach campaigns to address risky sexual behaviour and to promote the use of condoms and other protective strategies. These interventions should involve all relevant parties: non-governmental and governmental organizations, health providers, public-health experts and gay-related agencies. The message about the continuing risks and dangers of HIV/AIDS should go through multiple routes to address as many men as possible through the internet, media, clubs, bars and public spaces, to reinforce consistent condom use and other risk-reduction strategies, and to promote early diagnosis and treatment.Such campaigns should address both HIV-negative and HIV-positive men, but with a different focus on the needs of each. HIV-negative MSM should be informed about the possible routes of HIV transmission, the importance of using condoms, improving negotiation skills and other risk-reduction strategies to protect themselves and their partners. Innovative interventions could also attempt to associate the strong motivation of MSM for masculinity with the use of condoms. Additionally, frequent HIV testing in MSM-friendly clinics and community settings should be encouraged to detect new infections as early as possible. HIV-infected MSM should be instructed with safe-sex recommendations and prescribed HAART to reduce seminal viral load. Intervention in this group should address the unique psychological, social and medical status of each patient. As pointed out above, it crucially requires the involvement and engagement of the gay community themselves to maintain effective and acceptable interventions.Health educators must also respect the needs, wishes and behaviour of MSM when addressing them about the risk of HIV/AIDS, and making recommendations about safe-sex practices. Although condoms are indeed efficient at preventing HIV transmission, they might nonetheless be the ‘incorrect'' instrument in the ‘wrong'' place for many people. Condom use breaks the intimacy and spontaneity of sex and reduces the pleasure. Although we hope that we can convince a young, HIV-positive MSM to use condoms, this might not be a realistic goal. As such, addressing the risks requires a sensitive, ‘down-to-earth'' approach that respects gay culture and the dynamic of finding partners, as well as training physicians to provide counselling for MSM in a friendly and confident way.Reducing the use of illicit drugs in both HIV-infected and uninfected MSM is another priority, although in some cases drugs are used to cope with the stress related to living with HIV. Appropriate interventions for HIV-infected MSM must therefore include stress-reduction techniques, psychological services and counselling about the negative effects of substance use. Another public-health priority is to promote the disclosure of HIV status as part of the ethics related to using gay-dating sites. As the perceived threat of HIV has diminished owing to the success of ART and the non-fatal medical prognosis of HIV/AIDS, noticeable messages should be more positive and reflect contemporary gay life, using gay-related and non-gay-related venues frequented by MSM, such as gyms, airports, shops or tourist resorts.To address the problem and slow or halt the pandemic requires focused, evidence-based measures that respect biological, emotional and social aspects in a holistic approach…In conclusion, HIV prevalence among MSM remains high and, given the increase in survival of HIV-infected individuals and the high rate of new infections, this hyper-endemic state is likely to be sustained in developed countries [14]. To address the problem and slow or halt the pandemic requires focused, evidence-based measures that respect biological, emotional and social aspects in a holistic approach [24], taking into account psychological stressors, drug habits, discrimination and the quest for intimacy. It is also important to increase the sensitivity of health providers towards the special needs of MSM, to conduct open and non-judgemental discussions with their patients. A supportive medical environment can encourage MSM to adhere to periodical HIV testing, HBV and hepatitis A virus immunizations and, possibly, to comply with condom use [19]. Finally, due to the similarities in MSM behaviours in industrialized countries, a closer collaboration is required between researchers from countries that have large MSM communities. We are entering the fourth decade of the AIDS epidemic, and despite awareness among MSM of their greater vulnerability to HIV and the introduction of new medical interventions, the rate of new infections continues to rise disproportionately. It is time for new interventions.? Open in a separate windowZohar MorOpen in a separate windowMichael Dan