Human Papillomavirus Vaccination Optimal at Younger Ages, Prior to Sexual Debut

The human papillomavirus (HPV) vaccine effectively protects against anorectal HPV infection among men who have sex with men (MSM) when administered at younger ages or shortly following sexual debut. These study results were published in the Journal of Infectious Diseases.

This prospective cohort study was conducted between 2017 and 2019 among MSM from Montreal, Toronto, and Vancouver, Canada. The primary objective was to determine HPV vaccine effectiveness (VE) and longitudinal outcomes among this population. Researchers compared 12-month incidence and persistence of anorectal HPV infection between vaccinated and unvaccinated participants. Participants self-reported HPV vaccination status via digital questionnaire and submitted self-collected anal specimens for HPV DNA testing at baseline and 12 months. Propensity score weighted-modified Poisson regression was performed to balance covariates between the cohorts. Incidence rates (IRs) were calculated per 1000 person-months.

A total of 248 participants were included in the final analysis, of whom the median age at baseline was 26 (IQR, 24-28) years, 42.8% reported more than 5 sexual partners in the past 6 months, and 5.3% had HIV infection. Of these participants, 109 (44.0%) received at least 1 HPV vaccine dose at baseline. Among 139 participants who were unvaccinated at baseline, 23.7% received at least 1 HPV vaccine dose at 12 months.

For participants in the vaccinated cohort, 8.3% (IR, 6.8; 95% CI, 3.5-13.1) and 19.3% (IR, 16.9; 95% CI, 11.0-25.8) had at least 1 newly-acquired 9vHPV or 4vHPV type detected at 12 months, respectively. In the unvaccinated cohort, 12.2% (IR, 10.4; 95% CI, 6.5-16.7) and 20.9% (IR 18.6; 95% CI, 13.0-26.8) of participants had at least 1 newly-acquired 4vHPV or 9vHPV type detected at 12 months, respectively.

The overall VE was 44% (95% CI, 31%-76%), with a VE of 47% (95% CI, 14%-75%) for protection against persistent infection caused by at least 1 4vHPV type. In participants who received the first HPV vaccine at 23 years of age and younger, the VE was 92% (95% CI, 41%-99%) for protection against persistent infection attributed to at least 1 4vHPV type.

Limitations of this study include the small sample size and the inability to differentiate between recurrent infection and reactivation of a latent infection. Additionally, the time between vaccination and HPV infection onset was unknown.

According to the researchers “Our findings support national guidelines that recommend HPV vaccination at younger ages, ideally prior to sexual activity, for optimal protection.”

Disclosure: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Infectious Disease Advisor