MSM in Kenya urgently require targeted HIV prevention

Men who have sex with men (MSM) in Kenya urgently need targeted, HIV risk-reduction prevention information, according to the first study describing HIV prevalence and risk factors in a large group of East African MSM. The study is published in the November 2007 edition of AIDS.

In contrast with Western studies, the role of homosexuality and anal sex in the African HIV epidemic has received little attention. While active populations of MSM have long been known to exist in East Africa, their vulnerability to HIV infection has been largely ignored. The first study of HIV amongst MSM from Africa was published only in 2005.

The lack of research has been partly due to the fact that sex between men remains illegal and socially stigmatised in many African countries, and political and cultural barriers make research into anal intercourse difficult.

In order to address this information need and to guide HIV prevention efforts, research was conducted during enrollment into a vaccine preparedness cohort study in Mombasa, Kenya with the aim of assessing the risk factors for prevalent HIV infection among MSM.

Targeted recruitment of MSM for the vaccine preparedness cohort study began in 2005. Identification and recruitment of potential MSM study participants was conducted by a team of ten – 15 trained peer mobilisers. Participants were approached via personal networks and at venues at which MSM meet to establish contact with partners and clients. The criteria for MSM enrollment was a self-report of any anal sex within the last three months.

Upon enrollment, a detailed sociodemographic and sexual behavioural history was established by face-to-face interview. Participants were asked if they had previously tested for HIV, and if so the result (if known). Blood was collected for HIV and syphilis screening following the risk assessment. Multivariate logistic regression assessed risk factors for HIV infection.

Between August 2005 and April 2007, 285 MSM were identified; 114 men reported sex with men exclusively (MSME) and 171 men reported sex with both men and women (MSMW). MSM formed approximately one-third of the vaccine-feasibility enrollment population screened; other risk groups screened included 339 women and 210 men at high risk of heterosexually acquired HIV infection.

HIV prevalence was 43.0% (95% confidence interval (CI), 34–52%) for MSME and 12.3% (95% CI, 7–17%) for MSMW. Overall HIV prevalence for MSM at enrollment was 24.5% (95% CI, 19.7–30.7%). By contrast, HIV prevalence at cohort enrollment was 31.5% (95% CI, 27–36%) for female sex workers and 12.4% (95% CI, 8–17%) for high risk heterosexual men. Overall, 25.3% of MSM reported previous HIV testing, of whom five MSME and two MSMW disclosed that they had tested HIV positive.

Of MSM who reported anal intercourse in the last three months, 37% reported that all episodes had been without condoms. Over three-quarters of MSM (82%), reported at least one episode of unprotected anal intercourse with any partner in the last thee months. Eighty-six (75%) MSME and 69 (40%) MSMW reported recent receptive anal sex. Both anal receptive and insertive sex was reported by 25% of MSME and 32% of MSMW.

Men who reported sex with men exclusively had a high HIV prevalence (43.0%), which was significantly higher than bisexual men (12.3%). MSME were also more likely than MSMW to have serological evidence of active syphilis (7.0% versus 1.2%).

Receptive anal sex in the past three months was strongly associated with HIV infection (unadjusted OR, 4.7; 95% CI, 2.4–9.2). This association persisted when adjusted for age group, religious group, partner preference, anal intercourse without condom, intravenous drug use, paying for sex and prior negative testing for HIV-1 (OR, 6.1; 95% CI, 2.4–15.5).

In comparison with persons reporting only insertive anal intercourse, the risk of HIV was significantly higher for those reporting only receptive anal intercourse and higher still for those reporting both.

Recent intravenous drug use was strongly associated with HIV infection, but this was rarely reported. Only four participants (1.4%) reported the use of intravenous drug use in the last 3 months. HIV-1 infection was also associated with increasing age (OR, 1.1 per year; 95% CI, 1.04–1.12).

While exclusive sex with men was associated with HIV infection (OR, 6.3; 95% CI, 2.3–17), comparing MSME with MSMW, there were no differences in numbers of regular or casual partners in the last month. However, MSMW were significantly more likely to have paid another person for sex and MSME were significantly more likely than MSMW to have practiced receptive anal intercourse and significantly less likely to have practiced insertive anal intercourse.

The authors suggested that plausible explanations for their finding that men paying for sexual services in the past three months were less likely to be HIV-positive could include more consistent condom use or higher rates of insertive role-taking when sex is purchased. However they were not able to explore this further due to data limitations.

Most MSM (74%) reported selling sex for money or goods in the previous three months, of whom 40% reported buying sex as well. MSM selling sex were more likely to report unprotected sex with casual partners in the last week. Most clients (93%) were local residents. However, the researchers suggested that the high number of sex workers in this study is not general to all MSM in Mombasa as their sampling method was more likely to recruit sex workers. Only 49 MSM (17%) reported neither selling nor buying sex in this study.

The authors concluded that the high HIV prevalence seen among MSM in this study contrasts with the 2005 UNAIDS estimate for adult prevalence (15 – 49 years) of 6.1% (95% CI, 5.2–7.0%) in Kenya and calls for urgent public health action.

“The MSM in this study reported high levels of receptive anal intercourse and very low condom use,” they said. “The majority of these MSM were paid for sex in the previous three months, and commercial sex was associated with greater sexual risk-taking.”

They also noted that the study rejects the hypothesis that the local MSM sex trade exists to cater for demand by international visitors.

When commenting on the distinct lack of services for the prevention, diagnosis, and treatment of diseases transmitted by anal sex, and of interventions targeted toward MSM, they commented that, “the provision of appropriate interventions targeting high risk, marginalized groups will be crucial to further advances in HIV-1 prevention.”