HPV vaccination and anal HPV infection in gay, bisexual, and other men who have sex with men

Background: Gay, bisexual, and other men who have sex with men (gbMSM) have a higher risk of human papillomavirus (HPV) infection and related diseases and would benefit from preventive measures such as HPV vaccination. We assessed the association between HPV vaccination and anal HPV infection in HIV-negative gbMSM and gbMSM living with HIV from the Lubricant Investigation in Men to Inhibit Transmission of HPV Infection study.

Methods: Participants attended 7 visits over 12 months where they provided a nurse-collected anal sample and self-completed a questionnaire on risk factors and HPV vaccination. Samples were tested for HPV using polymerase chain reaction assays. We assessed the association with HPV vaccination and anal HPV prevalence and incidence using logistic and Cox regression, respectively. Analyses at the individual- (unit of analysis = participant) and HPV-level (unit of analysis = HPV type) considered vaccine-targeted types (any of HPVs 6/11/16/18) as the outcome. To assess construct validity, we repeated analyses considering incidence of non-vaccine-targeted (within- and cross-species) HPV types at the HPV-level. Estimates were adjusted for a propensity score to predict cumulative HPV positivity based on selected study and participant characteristics.

Results: Of 258 enrolled participants (18.2-71.7 years; 69 being HIV-positive), 23.3 % were vaccinated at baseline. At the individual-level, there was no association between vaccination and HPVs 6/11/16/18 prevalence (n = 250, aOR = 1.12, 95 % CI = 0.56-2.22) or incidence (n = 152, aHR = 0.34, 95 % CI = 2.19 × 10^-18-1.38). At the HPV-level, while there was no association with HPVs 6/11/16/18 prevalence (n = 1000, aOR = 0.99, 95 % CI = 0.57-1.71), vaccination was associated with a reduction in HPVs 6/11/16/18 incidence (n = 754, aHR = 0.22, 95 % CI = 6.01 × 10^-18-0.79). Vaccination was not associated with incidence of within-species (n = 2299, aHR = 0.76, CI = 0.42-1.24) or cross-species (n = 3774, aHR = 1.28, CI = 0.89-1.85) HPV types. Results were similar by HIV status.

Conclusion: Our findings support that HPV vaccination protects against incident anal infection of vaccine-targeted HPV types, thus, gbMSM should be encouraged to get vaccinated against HPV.