High prevalence of vaccine-preventable anal human papillomavirus infections is associated with HIV infection among gay, bisexual, and men who have sex with men in Nairobi, Kenya.

BACKGROUND: Human papillomavirus (HPV) infection is associated with anal cancers and is more prevalent in gay, bisexual, and men who have sex with men (gbMSM), partly due to their vulnerability to HIV infection. Baseline HPV genotype distributions and risk factors can inform the design of next-generation HPV vaccines to prevent anal cancer. METHODS: A cross-sectional study was conducted among gbMSM receiving care at a HIV/STI clinic in Nairobi, Kenya. Anal swabs were genotyped using a Luminex microsphere array. Multiple logistic regression methods were used to identify risk factors for four HPV outcomes (any HPV, any HR-HPV, and 4- and 9-valent vaccine-preventable HPVs). RESULTS: Among 115 gbMSM, 51 (44.3%) were HIV-infected. Overall HPV prevalence was 51.3%; 84.3% among gbMSM living with HIV and 24.6% among gbMSM without HIV (p < 0.001). One-third (32.2%) had HR-HPV and the most prevalent vaccine-preventable HR-HPV genotypes were 16, 35, 45, and 58. HPV-18 was uncommon (n = 2). The 9-valent Gardasil vaccine would have prevented 61.0% of HPV types observed in this population. In multivariate analyses, HIV status was the only significant risk factor for any HPV (adjusted odds ratio [aOR]:23.0, 95% confidence interval [95% CI]: 7.3-86.0, p < 0.001) and for HR-HPV (aOR: 8.9, 95% CI: 2.8-36.0, p < 0.001). Similar findings were obtained for vaccine-preventable HPVs. Being married to a woman significantly increased the odds of having HR-HPV infections (aOR: 8.1, 95% CI: 1.6-52.0, p = 0.016). CONCLUSIONS: GbMSM living with HIV in Kenya are at higher risk of anal HPV infections including genotypes that are preventable with available vaccines. Our findings support the need for a targeted HPV vaccination campaign in this population.

Rectal microbiota diversity in Kenyan MSM is inversely associated with frequency of receptive anal sex, independent of HIV status.

OBJECTIVE: Both HIV infection and identifying as MSM have been linked to altered rectal microbiota composition, but few studies have studied sexual behavioural associations with rectal microbiota within MSM. In addition, most rectal microbiota studies in MSM have been limited geographically to Europe and North America, and replication of findings in lower and middle-income countries is lacking. DESIGN: A cross-sectional study. METHODS: We enrolled MSM from Nairobi, Kenya, and determined their HIV/sexually transmitted infection status. Rectal specimens were obtained for 16s rRNA sequencing of the rectal microbiota, and sexual behaviour was characterized using a standardized questionnaire. Microbiome differences were modelled using nonparametric statistics, Bray-Curtis ecological distance metrics and analyses of differential taxa abundance. Multivariable linear regression was used to model HIV status and recent sexual activity as predictors of alpha diversity, controlling for a range of covariates. RESULTS: Alpha diversity was consistently lower in Kenyan HIV-infected MSM (n = 80), including those on antiretroviral therapy (ART) compared with HIV-uninfected MSM. A statistical trend was observed for clustering of HIV status by Prevotella or Bacteroides dominance (P = 0.13). Several taxa were enriched in HIV-positive men, including Roseburia, Lachnospira, Streptococcus and Granulicatella. Receptive anal sex with several types of sexual partners (paying, regular, casual) was associated with lower Chao1 and Simpson diversity, independent of HIV status, while HIV infection was associated lower Chao1 (P = 0.030) but not Simpson diversity (P = 0.49). CONCLUSION: Both HIV infection and sexual behaviour were associated with rectal microflora alpha diversity, in particular richness, but not Prevotella spp. dominance, in Kenyan MSM. Associations were more robust for sexual behaviour.