Canada: Oral HPV prevalence among young MSM low with publicly-funded vaccine programs

The prevalence of oral human papillomavirus (HPV) was found to be low among a population of young, urban men who have sex with men (MSM) in Canada following the introduction of publicly-funded HPV vaccination programs, according to study results published in The Journal of Infectious Diseases.

Between February 2017 and August 2019, researchers conducted a cross-sectional analysis of a community-based prospective sexual cohort health study involving gay, bisexual, and other MSM residing in Canada. The researchers aimed to estimate the prevalence of oral HPV infection after the introduction of publicly-funded vaccination programs. Patients eligible for the analysis were aged 16 to 30 years and stratified by city of residence, vaccination status, and age at enrollment. The patients self-collected oral rinse specimens for HPV testing and positive specimens were genotyped for 36 HPV types via polymerase chain reaction. Outcomes were compared between patients who reported receipt of at least 1 HPV vaccine dose and those who were unvaccinated. Chi-square, Fisher exact, Wilcoxon-rank sum, and Kruskal-Wallis testing were used for statistical analyses.

A total of 838 patients (median age, 26 years; gay, 78.6%; living with HIV, 5.4%; current smoker, 46.6%) were included in the analysis, of whom 389 (46.4%), 212 (25.3%), and 237 (28.3%) resided in Montreal, Toronto, and Vancouver, respectively. The median age at first oral sex with a man was 17 (IQR, 15-19) years.

Overall, 309 (36.9%) patients reported receipt of at least 1 dose of the HPV vaccine. The median age at vaccination was 23 (IQR, 21-25) years. Positive vaccination status significantly varied by city (Montreal, 32.4%; Toronto, 37.7%; and Vancouver, 43.5%), and most (90%) vaccinated patients reported receipt of their first dose within the same year or 1 year after their first oral sex encounter.

In regard to oral HPV prevalence, at least 1 HPV genotype was detected in 22 patients (2.6%; 95% CI, 1.5-3.7). The researchers noted detectable high- and low-risk genotypes in 1.2% (95% CI, 0.5-1.9) and 1.6% (95% CI, 0.7-2.4) of the total population, respectively.

Of the 22 patients with detectable oral HPV, 4 were infected with 2 HPV types each. The highest detection rates were for HPV16, HPV44, and HPV51 (11.5%), followed by HPV84 and HPV6 (7.7%).

Further analysis after stratification by HPV vaccine status showed that vaccinated patients were at reduced risk for oral 4-valent (odds ratio [OR], 0.3; 95% CI, 0.0-2.6) and 9-valent (OR, 0.4; 95% CI, 0.1-2.1) HPV infections, corresponding to vaccine effectiveness estimates of 70% (95% CI, -161 to 96) and 57% (95% CI, -110 to 91), respectively.

Study limitations include the small numerator counts for oral HPV outcomes, potential misclassification bias, the inability to performed adjusted regression analyses, the cross-sectional design, and potential lack of generalizability to other populations.

“Given the absence of screening guidelines for oropharyngeal cancer, this research may further promote efforts to expand HPV vaccination coverage, especially before sexual debut, a critical step in preventing HPV-associated cancers, including oral cancer,” the researchers concluded.

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

By Paul Basilio

References:

Alessandrini J, Cox J, de Pokomandy A, et al. Prevalence of oral human papillomavirus among urban gay, bisexual, and other men who have sex with men in Canada, 2017-2019.  J Infect Dis. Published online July 23, 2024. doi:10.1093/infdis/jiae345