Unusual and unique distribution of anal high-risk human papillomavirus (HR-HPV) among men who have sex with men living in the Central African Republic

Abstract

Background: High-risk (HR) human papillomavirus (HPV) infection remains a great concern in relation to African men who have sex with men (MSM), especially those infected with HIV. The prevalence of HR-HPV and associated risk factors was estimated in a cross-sectional observational study covering MSM living in Bangui, Central African Republic.

Methods: MSM receiving care at the Centre National de Référence des Infections Sexuellement Transmissibles et de la Thérapie Antirétrovirale, Bangui, were included. HIV serostatus and socio-demographic and behavioral characteristics were collected. HPV DNA was detected and genotyped on anal swabs using Anyplex™ II HPV28 test (Seegene, South Korea), and HSV DNA by in-house real-time PCR. Logistic regression analyses were used to determine risk factors associated with HPV outcomes.

Results: 42 MSM (mean age, 23.2 years; range, 14-39) including 69.1% HIV-1-positive and 30.9% HIV-negative were prospectively enrolled. The prevalence of anal HPV was 69.1%, including 82.7% of HR-HPV which were multiple in 52.0%. The most prevalent genotypes were HPV-35, HPV-58, HPV-59 and HPV-31. While, HPV-16 and HPV-18 were present in a minority of samples. Multiple HR-HPV infection was more frequent in HIV-positive MSM (41.4%) with 2.7 genotypes per anal samples than in HIV-negative (7.7%) with 1.5 genotypes per anal samples. HPV types included in the prophylactic Gardasil-9® vaccine were detected in 68.9% of specimens and HPV-58 was the most frequently detected. MSM infected by HPV-16 and HPV-18 were all infected by HIV-1. Few anal swabs (11.9%) contained HSV-2 DNA without relationship with HPV detection. Condomless receptive anal intercourse was the main risk factor to being infected with any type of HPV and condomless insertive anal intercourse was significantly less associated with HPV contamination than receptive anal intercourse (Odd ratio = 0.02).

Conclusion: MSM in Bangui are at-risk of HIV and HR-HPV anal infections. The unusual distribution of HPV-35 as predominant HPV suggests possible geographic specificities in the molecular epidemiology of HR-HPV in sub-Saharan Africa. Scaling up prevention strategies against HPV infection and related cancers adapted for MSM in Africa should be prioritized. Innovative interventions should be conceived for the MSM population living in Bangui.

Fig 1. Distribution of anal HPV types included (or not included) in the 9-valent Gardasil-9® vaccine.

Number of low-risk (LR) and high-risk (HR) HPV genotypes in 29 anal swabs positive for HPV DNA by molecular biology according to their possible prevention by 9-valent HPV vaccine among study men who have sex with men (n = 42) living in the Central African Republic. Nota bene. The 9-valent Gardasil-9® vaccine (Merck & Co. Inc., New Jersey, USA) is effective against HPV genotypes 6, 11, 16, 18, 31, 33, 45, 52 and 58.

Fig 2. Distribution of anal HPV types according to the HIV-serostatus.

Number of low-risk (LR) and high-risk (HR) HPV genotypes in 29 anal swab positive for HPV DNA by molecular biology according to HIV-serostatus among study men who have sex with men (n = 42) living in the Central African Republic.