HIV-negative Homosexual Men In Sydney Research Articles

Homosexual men in HIV serodiscordant relationships: implications for HIV treatment as prevention research

IntroductionStudies in heterosexual HIV serodiscordant couples have provided critical evidence on the role of HIV treatments in reducing HIV transmission risk. However, there are limited data regarding the effect of treatment on HIV transmission in homosexual male couples. We examined features of male homosexual HIV serodiscordant relationships that may impact upon the design of HIV treatment and transmission studies.MethodsData were from a prospective cohort study of HIV-negative homosexual men in Sydney, Australia. Men were followed up with six-monthly interviews and annual testing for HIV. Characteristics of men in HIV serodiscordant and seroconcordant relationships at baseline were compared, and a longitudinal analysis performed of rate of relationship break-up and of HIV incidence.ResultsAt baseline, 5.5% of participants (n=79) had an HIV-positive partner. Most (80.8%) of these relationships were non-monogamous, and 36.7% of men reported recent unprotected anal intercourse (UAI) with casual partners. The rate of relationship break-up was 29.5 per 100 person-years. Half of men in serodiscordant relationships (49.4%) reported recent UAI with their regular partners. HIV incidence was 2.2 per 100 person-years. It was substantially higher in relationships of less than one year's duration (6.1 per 100 person-years) and in men who reported unprotected receptive anal intercourse with ejaculation with their regular partners (15.5 per 100 person-years).ConclusionsLevels of HIV transmission risk and incidence were high, particularly in early relationships. Rates of relationship break-up were high. These data suggest that studies of HIV treatments and transmission in homosexual serodiscordant couples should focus on early relationships so as not to underestimate risk, and sample sizes must allow for high rates of relationship break-up.

Sexual Partner’s Age as a Risk Factor for HIV Seroconversion in a Cohort of HIV-Negative Homosexual Men in Sydney

Increasing partner age may be an important risk factor for HIV infection in homosexual men. About 20% of 1,427 participants in the Health in Men study in Sydney, Australia, reported that half or more of their partners were much older. Having more partners who were much older was associated with an increased risk of HIV seroconversion (p trend=0.002), and this remained significant after adjustment for participants' age, number of regular and casual partners, and sexual risk behaviour (p trend=0.027). Men who reported much older partners were at increased risk of HIV infection, independent of unprotected anal intercourse with sero-nonconcordant partners.

The Impact of HIV Seroadaptive Behaviors on Sexually Transmissible Infections in HIV-Negative Homosexual Men in Sydney, Australia

Human immunodeficiency virus (HIV) seroadaptive behaviors, such as serosorting and strategic positioning, are being increasingly practised by homosexual men; however, their impact on sexually transmissible infections is unclear. Participants were 1427 initially HIV-negative men enrolled from 2001 to 2004 and followed to June 2007. Participants were tested annually for anal and urethral gonorrhoea and chlamydia, herpes simplex virus, and syphilis. In addition, they reported diagnoses of these conditions, and of genital and anal warts between annual visits, and sexual risk behaviors. Compared with men who reported no unprotected anal intercourse (UAI), serosorting was associated with an increased risk of urethral (incidence: 6.06 vs. 3.56 per 100 person-years (PY), hazard ratio (HR) = 1.97, 95% confidence interval [CI]: 1.43-2.72) and anal (incidence 3.95 vs. 2.80 per 100 PY, HR = 1.62, 95% CI: 1.11-2.36) chlamydia. Compared with men who reported UAI with HIV nonconcordant partners, men who practised serosorting had significantly lower risk of incident syphilis (incidence 0.18 vs. 1.00 per 100 PY, HR = 0.21, 95% CI: 0.05-0.81) and urethral gonorrhoea (incidence 2.15 vs. 5.52 per 100 PY, HR = 0.61, 95% CI: 0.39-0.96). Compared with men who reported no UAI, strategic positioning was associated with an increased risk of urethral gonorrhoea (incidence 4.11 vs. 2.10 per 100 PY, HR = 1.72, 95% CI: 1.05-2.83) and chlamydia (incidence 8.71 vs. 3.56 per 100 PY, HR = 2.22, 95% CI: 1.55-3.18). Compared with men who reported receptive UAI, the incidence of anal gonorrhoea (incidence 1.48 vs. 3.83 per 100 PY, HR = 0.38, 0.20-0.74) and chlamydia (incidence 3.10 vs. 6.30 per 100 PY, HR = 0.44, 95% CI: 0.27-0.69) was significantly lower in those who practised strategic positioning. For men who reported seroadaptive behaviors, rates of some bacterial sexually transmissible infections were higher than in men who reported no UAI. However, rates were lower than for men who reported higher HIV risk behaviors.

Gay Men are Less Likely to Use Condoms with Casual Sex Partners They Know ‘Well’

Health in Men (HIM) was an open cohort study of 1,427 HIV-negative homosexual men in Sydney. The majority of respondents' unprotected anal intercourse (UAIC) events were with partners whose HIV status they did not know. Nonetheless, with casual partners with whom they engaged in UAIC, respondents indicated that they knew 'well' 28.9% of the HIV-negative partners and 26.2% of HIV-positive partners, but only 7.6% of the HIV status unknown partners. Respondents were more likely to have engaged in UAIC with partners they knew well (McNemar P < 0.001). The challenge for HIV prevention is that many gay men's decisions about condom use may be driven as much by their relationship with individual partners as their commitment to 'safe sex'.

Per-contact probability of HIV transmission in homosexual men in Sydney in the era of HAART

The objective of this study is to estimate per-contact probability of HIV transmission in homosexual men due to unprotected anal intercourse (UAI) in the era of HAART. Data were collected from a longitudinal cohort study of community-based HIV-negative homosexual men in Sydney, Australia. A total of 1427 participants were recruited from June 2001 to December 2004. They were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV till June 2007. Data were used in a bootstrapping method, coupled with a statistical analysis that optimized a likelihood function for estimating the per-exposure risks of HIV transmission due to various forms of UAI. During the study, 53 HIV seroconversion cases were identified. The estimated per-contact probability of HIV transmission for receptive UAI was 1.43% [95% confidence interval (CI) 0.48-2.85] if ejaculation occurred inside the rectum, and it was 0.65% (95% CI 0.15-1.53) if withdrawal prior to ejaculation was involved. The estimated transmission rate for insertive UAI in participants who were circumcised was 0.11% (95% CI 0.02-0.24), and it was 0.62% (95% CI 0.07-1.68) in uncircumcised men. Thus, receptive UAI with ejaculation was found to be approximately twice as risky as receptive UAI with withdrawal or insertive UAI for uncircumcised men and over 10 times as risky as insertive UAI for circumcised men. Despite the fact that a high proportion of HIV-infected men are on antiretroviral treatment and have undetectable viral load, the per-contact probability of HIV transmission due to UAI is similar to estimates reported from developed country settings in the pre-HAART era.

Anal Sexually Transmitted Infections and Risk of HIV Infection in Homosexual Men

We examined a range of common bacterial and viral sexually transmitted infections as risk factors for HIV seroconversion in a community-based cohort of HIV-negative homosexual men in Sydney, Australia. Detailed information about HIV risk behaviors was collected by interview twice yearly. Participants were tested annually for HIV, anal and urethral gonorrhea and chlamydia, herpes simplex virus types 1 and 2, and syphilis. In addition, they reported annual diagnoses of these conditions and of genital and anal warts. Among 1427 enrolled participants, 53 HIV seroconverters were identified, giving an incidence of 0.78 per 100 person-years. After controlling for number of episodes of insertive and receptive nonseroconcordant unprotected anal intercourse, there were independent associations with anal gonorrhea (adjusted hazard ratio = 7.12, 95% confidence interval: 2.05 to 24.79) and anal warts (hazard ratio = 3.63, 95% confidence interval: 1.62 to 8.14). Anal gonorrhea and anal warts were independently associated with HIV acquisition. The added HIV prevention value of more frequent screening of the anus to allow early detection and treatment of anal sexually transmitted infections in homosexual men should be considered.

Prevalence, incidence and risk factors for pharyngeal gonorrhoea in a community-based HIV-negative cohort of homosexual men in Sydney, Australia

BackgroundPharyngeal gonorrhoea is common in homosexual men and may be important in maintaining community prevalence of anogenital infections.MethodsFrom 2003, all participants in the Health in Men cohort of HIV-negative homosexual...

Nonoccupational postexposure prophylaxis, subsequent risk behaviour and HIV incidence in a cohort of Australian homosexual men

To investigate the relationship between nonoccupational postexposure prophylaxis (NPEP) use and future HIV risk behaviours and HIV infection in a cohort of HIV-negative homosexual men in Sydney, Australia. Prospective analysis of NPEP use in a community cohort from 2001 to 2007. In the Health in Men study cohort, men were annually questioned about NPEP use and tested for HIV. Every 6 months, detailed quantitative data on unprotected anal intercourse were collected. Cox regression models examined risk factors for incident NPEP use, HIV seroconversion and time trends in NPEP use. The change in the number of unprotected anal intercourse acts with nonseroconcordant partners before and after NPEP was examined using the Wilcoxon signed-rank test. One thousand four hundred and twenty-seven participants were enrolled. At baseline, 78.5% of participants had heard of NPEP, which increased to 97.4% by the fifth annual interview. NPEP use increased significantly from 2.9 per 100 person-years in 2002 to 7.1 per 100 person-years in 2007 (P = 0.007). Unprotected anal intercourse was a strong predictor of incident NPEP use. Use of NPEP was not associated with changes in HIV risk behaviour. Men who received NPEP had a significantly higher rate of subsequent HIV seroconversion (hazard ratio 2.67, 95% confidence interval 1.40-5.08, P = 0.003). Awareness of the availability of NPEP in this cohort was nearly universal. Use was common and increased rapidly over the study period. NPEP was targeted mostly towards high-risk behaviours. Use of NPEP was not associated with reductions in risk behaviour, and men who received NPEP continued to be at high risk of subsequent HIV infection.

Unprotected anal intercourse, risk reduction behaviours, and subsequent HIV infection in a cohort of homosexual men

A range of risk reduction behaviours in which homosexual men practise unprotected anal intercourse (UAI) has been described. We aimed to assess the extent of any reduction in HIV risk associated with these behaviours. A prospective cohort study of HIV-negative homosexual men in Sydney, Australia. Men were followed up with 6-monthly detailed behavioural interviews and annual testing for HIV. The four risk reduction behaviours (behaviourally defined) examined were serosorting, negotiated safety, strategic positioning, and withdrawal during receptive UAI (UAI-R). In 88% of follow-up periods in which UAI was reported, it occurred in the context of consistent risk reduction behaviours. Compared with those who reported no UAI, the risk of HIV infection was not raised in negotiated safety [hazard ratio = 1.67, 95% confidence interval (CI) 0.59-4.76] and strategic positioning (hazard ratio = 1.54, 95% CI 0.45-5.26). Serosorting outside negotiated safety was associated with an intermediate rate of HIV infection (hazard ratio = 3.11, 95% CI 1.09-8.88). Withdrawal was associated with a higher risk than no UAI (hazard ratio = 5.00, 95% CI 1.94-12.92). Patterns of UAI differed greatly according to partner's serostatus. Men who reported serosorting were less likely to report either strategic positioning or withdrawal. Each behaviour examined was associated with an intermediate HIV incidence between the lowest and highest risk sexual behaviours. The inverse association between individual behaviours suggests that men who practise serosorting rely on this protection. The high prevalence of these behaviours demands that researchers address the contexts and risks associated with specific types of UAI.

Hepatitis A and B infection and vaccination in a cohort of homosexual men in Sydney

To determine the prevalence and incidence of hepatitis A (HAV) and B (HBV) infection and vaccination in HIV-negative homosexual men in Sydney, and associated risk factors. An open prospective cohort study was conducted among a community-based sample of HIV-negative homosexual men in Sydney in 2001-02. Participants underwent a face-to-face interview, regarding demographics, sexual behavioural risk factors and sexually transmitted infections, and blood samples were collected. They were followed annually. Nine hundred and three men completed a baseline interview by the end of 2002. Among them, 68% were seropositive to hepatitis A. The seroprevalence of prior hepatitis B infection was 19%, and 53% had serological evidence of HBV vaccination. Younger men were much more likely to be seronegative, with 48% and 46% of <25-year-olds being seronegative to HAV and HBV respectively. In multivariate analysis HAV and HBV infection were associated with increasing age, greater number of lifetime sex partners and HBV infection was also associated with previous sexually transmitted infections. HAV vaccination was associated with increasing age, greater number of lifetime sex partners, overseas travel in the last year and self-reported anogenital warts. HBV vaccination was associated with higher occupational status, greater lifetime number of sex partners and previous sexually transmitted infections. Substantial proportions of gay community-attached young homosexual men are still at risk of HAV and HBV infection. This study points to a need for vaccination strategies which ensure high levels of hepatitis A and B immunity in young sexually active gay men.