Men who have sex with men (MSM), and in particular HIV+ MSM, show the greatest risk of anal HPV infection and the highest incidence of anal cancer. HPV vaccine should be ideally administered at an early age, before the first sexual intercourse. Since routine administration of HPV vaccine to young boys has begun only in recent years, currently the majority of immunized adult MSM individuals underwent vaccination after sexual debut. In the present study we aimed to evaluate vaccination rate and prevalence of anal HPV infection and anal dysplasia (squamous intraepithelial lesion, SIL) in HIV+ and HIV- MSM aged < 45 years that received HPV vaccination after the first sexual intercourse.
142 MSM, 110 HIV+ and 32 HIV-, younger than 45 years were included in the present study. All enrolled subjects underwent anal HPV DNA test for HPV identification and genotyping. The presence of anal dysplasia was assessed trough anal cytology or anal histology from anal biopsies collected during high resolution anoscopy.
Vaccination rate was similar between HIV+ and HIV- participants (20% vs. 31.3%; p=0.169). 76.3% of HIV+ participants and 57.1% of HIV- participants tested positive at anal HPV DNA test (p=0.042). Anal SIL of any grade was observed in 76.3% of HIV+ individuals and 53.6% of HIV- subjects (p=0.017).The prevalence of anal HPV infection was similar between vaccinated and unvaccinated HIV+ subjects (72.7% vs. 77.3%; p=0.864).Among vaccinated participants, HPV DNA tested positive in 72.7% of HIV+ and 33.3% of HIV- subjects (p=0.041). On the other hand, 77.3% of HIV+ unvaccinated and 68.4% of HIV- unvaccinated individuals showed a positive HPV DNA test (p=0.415).Among HIV+ participants, anal SIL was observed in 54.4% of vaccinated and 81.8% of unvaccinated individuals (p=0.01).Among vaccinated participants, the presence of anal SIL was detected in 54.5% of HIV+ and 33.3% of HIV- vaccinated participants (p=0.283). In unvaccinated participants SIL was detected in 81.8% of HIV+ and 63.1% of HIV- subjects (p=0.073).Being unvaccinated (OR 1.6; CI 95% 1.1-2.4), living with HIV (OR 2.8; CI 95% 1.2-6.6) and anal HPV infection (OR 6.7; CI 95% 2.9-15.4) were associated to an increased risk of anal dysplasia at multivariate analysis.
Even if administered after sexual debut, vaccination against HPV is useful in reducing the risk of anal dysplasia in HIV+ MSM aged < 45 years. Immunization against HPV should be encouraged, particularly in this population.