Men who have sex with men and HIV transmission risks in sub-Saharan Africa: a Kenyan case study

Introduction Men who have sex with men have been largely unrecognised within African HIV epidemics until recently. This thesis reports on three projects in Mombasa, Kenya and in Oxford that aimed to describe the burden and risk factors for HIV among MSM across sub-Saharan Africa and in Kenya specifically, and to describe patterns of sexual behaviour and partnerships relevant to individual and population HIV risk. Methods 1. cross-sectional study of HIV prevalence and risk factors among 285 MSM at enrolment to a vaccine feasibility cohort in Mtwapa, Kenya; 2. review and meta-analysis of behavioural and HIV studies in sub-Saharan African MSM until 2010 3. prospective, self-administered daily diary study of sexual behaviour among a sample of 83 IAVI vaccine feasibility cohort participants Main results HIV prevalence was 24.6% among MSM, who frequently reported transactional sex. Receptive anal sex practice, injecting drug use, concomitant STIs, homosexual exclusivity and age were independent risk factors for HIV prevalence. Prevalence studies identified high HIV burden among MSM across Africa, not associated with prevalence amongst the general adult population despite commonplace heterosexual behaviours. HIV prevalence associations with homosexual exclusivity, unprotected anal sex and transactional sex were largely consistent across different contexts. In Mombasa, prospective behaviour studies described a transactional sexual network serving both male and female clients, transaction dictating both relationship patterns and age differences between partners and condom use. Young age, homosexual exclusivity, alcohol use, religious affiliation and low earnings were associated with high risk homosexual behaviours. Heterosexual sex was commonplace, yet heterosexually active MSM had a significantly lower profile of homosexual behavioural HIV risk. Conclusions: There is an urgent need for African countries to identify MSM populations and deliver appropriate and relevant HIV prevention, treatment and care. Effective and accessible responses will benefit African MSM, and likely also enhance wider HIV control efforts.