Prevalence, genotype diversity and determinants of anal HPV infection in HIV-uninfected men having sex with men.

BACKGROUND: Anal human papillomavirus (HPV) infection is very common in men having sex with men (MSM), but the available data on its burden and characteristics mainly concern HIV-infected individuals.

OBJECTIVES: This study aimed to assess the prevalence, spectrum of genotypes, and determinants of the anal HPV infection in metropolitan HIV-1 uninfected MSM.

STUDY DESIGN: A cohort of 258 MSM (median age 32 years, IQR 26-39) enrolled at an STI Clinic was screened for anal HPV infection using a highly sensitive PCR-based genotyping method. Medical history and behavioral data were collected.

RESULTS: Overall, 74.8% of the MSM were HPV-positive, with 56.2% of the participants being infected by high-risk (HR) types. A multiple infection was detected in 65.3% of the HPV-positive MSM, with up to 10 different HPV types detected in the same sample. A broad spectrum of infecting HPV types was observed, with 36 different types found overall and HPV16 representing the most common type (17.8%). The lifetime and recent number of sexual partners as well as having receptive anal sex were significantly associated with the anal HPV infection, confirming the role of sexual behavior in risk of HPV infection. However, neither younger age at first intercourse nor inconsistent use of condom was significantly associated with the infection.

CONCLUSIONS: The present findings highlight the need to create a more significant awareness about the risk of anal HPV infection among HIV-uninfected MSM and warrant the investigation of possible anal intraepithelial lesions, particularly in view of the increasing anal cancer incidence in high-risk populations.