Anal human papillomavirus prevalence among vaccinated and unvaccinated gay, bisexual, and other men who have sex with men in Canada.

Abstract

BACKGROUND\nStarting in 2015, human papillomavirus (HPV) vaccine has been publicly funded for gay, bisexual, and other men who have sex with men (GBM) aged ≤26 years in Canada.\n\n\nMETHODS\nSelf-identified GBM who reported having sex with another man within the past six months were enrolled using respondent-driven sampling (RDS) between February 2017 and August 2019 in Montreal, Toronto, and Vancouver, Canada. Men aged 16-30 years self-collected anal specimens for HPV-DNA testing. Prevalence was estimated using RDS-II weights. We compared the prevalence of quadrivalent (HPV-6/11/16/18) and 9-valent (HPV-6/11/16/18/31/33/45/52/58) vaccine types between GBM who self-reported HPV vaccination (≥1 dose) and those reporting no vaccination using a modified Poisson regression for binary outcomes.\n\n\nRESULTS\nAmong 645 GBM who provided a valid anal specimen (median age = 26 years; 5.9% HIV-positive), 40.3% reported receiving ≥1 dose of HPV vaccine; of whom, 61.8% received 3 doses. One-quarter were infected with ≥1 quadrivalent type (crude = 25.7%, RDS-weighted = 24.4%). After adjustment for potential confounders, vaccinated GBM had a 27% lower anal prevalence of quadrivalent types compared to unvaccinated GBM (aPR = 0.73, 95%CI = 0.54-1.00). Lower prevalence ratios were found among vaccinated participants who were vaccinated >2 years before enrollment (aPR = 0.47, 95%CI = 0.25-0.86) or received their first vaccine dose at age ≤ 23 years (aPR = 0.64, 95%CI = 0.42-0.99). Point estimates were similar for ≥2 or 3 doses and 9-valent types.\n\n\nCONCLUSIONS\nHPV vaccination was associated with a lower anal prevalence of vaccine-preventable HPV types among young, sexually active GBM. Findings will help inform shared decision making around HPV vaccination for GBM and their healthcare providers.