Vaccine effectiveness against anal HPV among men who have sex with men aged 18-45 years attending sexual health clinics in three United States cities, 2018-2023.

ABSTRACT

BACKGROUND: We assessed human papillomavirus (HPV) vaccine effectiveness (VE) against anal HPV among men who have sex with men (MSM) in 2018-2023. METHODS: Residual anal specimens from MSM without HIV ages 18-45 years were tested for HPV. We calculated adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for associations between vaccination (≥1 dose) and quadrivalent vaccine (4vHPV)-type prevalence adjusting for city, race/ethnicity, and non-vaccine-type HPV prevalence, stratified by age group (18-26, 27-45). VE was calculated as (1-aPR)x100. RESULTS: Among 2802 persons aged 18-26, 4vHPV-type prevalence was lower in those vaccinated at age <18 (aPR=0.13, CI 0.08-0.22, VE=87%) and those vaccinated ≥2 years before specimen collection (aPR=0.52, CI 0.42-0.64, VE=48%), compared with unvaccinated persons. Among 3548 persons aged 27-45, 4vHPV-type prevalence was lower in those vaccinated at ages 18-26 (aPR=0.68, CI 0.57-0.82, VE=32%) and those vaccinated ≥2 years before specimen collection (aPR=0.66, CI 0.57-0.77, VE=33%), compared with unvaccinated persons. While we observed no VE in persons vaccinated at age >26 overall, 4vHPV-type prevalence was lower in the subgroup vaccinated ≥2 years before specimen collection (aPR=0.71, CI 0.56-0.89, VE=29%). CONCLUSIONS: We found high VE against anal 4vHPV-type prevalence among MSM aged 18-26 who were vaccinated at age <18. Lower VE was observed among MSM ages 27-45 who were vaccinated at age 18-26 or ≥2 years before specimen collection. While ideally vaccination should be given at younger ages, vaccination can prevent some future infections in this population.