Successes and challenges of HIV prevention in men who have sex with men

Abstract

Men who have sex with men (MSM) have been substantially affected by HIV epidemics worldwide. Epidemics in MSM are re-emerging in many high-income countries and gaining greater recognition in many low-income and middle-income countries. Better HIV prevention strategies are urgently needed. Our review of HIV prevention strategies for MSM identified several important themes. At the beginning of the epidemic, stand-alone behavioural interventions mostly aimed to reduce unprotected anal intercourse, which, although somewhat efficacious, did not reduce HIV transmission. Biomedical prevention strategies reduce the incidence of HIV infection. Delivery of barrier and biomedical interventions with coordinated behavioural and structural strategies could optimise the effectiveness of prevention. Modelling suggests that, with sufficient coverage, available interventions are sufficient to avert at least a quarter of new HIV infections in MSM in diverse countries. Scale-up of HIV prevention programmes for MSM is difficult because of homophobia and bias, suboptimum access to HIV testing and care, and financial constraints.

Figure 1. Effects of HIV prevention interventions for MSM, by number of MSM included in study, significance, and intervention type

Effect size is expressed as a risk ratio when possible, but in some cases represents an odds ratio or prevalence ratio. Outcome was unprotected anal intercourse in 54 cases, HIV or other sexually transmitted infection in five, and number of sex partners in one. Red halos show significance. The red dotted line signifies a null effect (ie, no increase or decrease in the targeted outcome). The appendix contains further information and references for included interventions. MSM = men who have sex with men. GLI = group-level intervention. ILI = individual-level intervention. CLI = community-level intervention.

Figure 2. Modelled estimation of proportion of infections averted in 10 years after provision of HIV prevention packages to men who have sex with men

Men were eligible for oral pre-exposure prophylaxis if they were HIV negative and either had unprotected anal intercourse with two or more men in the previous year, or were in an ongoing sexual relationship with a known HIV-positive partner. “Early” means treatment at a CD4 count of 500 cells per μL in the USA and 350 cells per μL in other countries. Coverage is estimated at 40% for oral pre-exposure prophylaxis and early antiretrovirals. A 20% replacement of unprotected anal intercourse with condom-protected intercourse is estimated for the condom package. Bars are the mean of ten simulations.

Figure 3. Stochastic simulation estimating the proportion of HIV infections averted in 10 years by an oral pre-exposure prophylaxis prevention package in men who have sex with men, by degree of coverage

Men were eligible for oral pre-exposure prophylaxis if they were HIV negative and either had unprotected anal intercourse with two or more men in the previous year, or were in an ongoing sexual relationship with a known HIV-positive partner. Each symbol is the result of a single simulation; variation is partly because of the size of the simulated population, which is arbitrary. The magnitude of the variation shows the extent of stochastic variation within each scenario, allowing for interpretation of the differences across scenarios and countries.

Figure 4. Stochastic simulation estimating the proportion of HIV infections averted in 10 years by an oral pre-exposure prophylaxis prevention package in men who have sex with men with 40% coverage, by degree of adherence

Men were eligible for oral pre-exposure prophylaxis if they were HIV negative and either had unprotected anal intercourse with two or more men in the previous year, or were in an ongoing sexual relationship with a known HIV-positive partner. Each symbol is a single simulation; variation is partly because of the size of the simulated population, which is arbitrary. The magnitude of the variation shows the extent of stochastic variation within each scenario, allowing for interpretation of the differences across scenarios and countries.