HPV Genotype Distribution in Unvaccinated Quebec Males Aged 16-20
Overview
This study assessed HPV prevalence among unvaccinated sexually active males aged 16 to 20 in Quebec, revealing an overall HPV prevalence of 18.4% but a very low prevalence (<1%) of quadrivalent HPV vaccine-targeted genotypes. The findings suggest strong herd immunity effects from the female vaccination program in this population.
Background
Quebec implemented a school-based HPV vaccination program in 2008 targeting girls, achieving over 90% coverage by age 15. In 2018, Quebec introduced a mixed HPV vaccine schedule combining nonavalent and bivalent vaccines. Evaluating the impact of new vaccine schedules requires understanding herd immunity, particularly among unvaccinated males who were not eligible for the public vaccination program. This study aimed to measure HPV genotype prevalence in unvaccinated young men to inform future vaccine schedule evaluations.
HPV prevalence among unvaccinated sexually active males aged 16–20 was 18.4%.
Prevalence of quadrivalent HPV vaccine-targeted genotypes was very low at 0.5%, with only 2 participants positive.
Both participants with quadrivalent vaccine-targeted genotypes reported sexual contact with men.
Age, higher number of lifetime sexual partners, and history of other sexually transmitted infections were independently associated with HPV positivity.
The low prevalence of vaccine-targeted genotypes suggests strong herd immunity from the female vaccination program.
Clinical Implications
The strong herd immunity observed among unvaccinated young men indicates that HPV vaccine-targeted genotypes are circulating at very low levels in this population. This should be considered when evaluating new HPV vaccination schedules, as unvaccinated individuals may already benefit indirectly from high female vaccination coverage. Continued surveillance is important to monitor HPV genotype prevalence and vaccine impact.
Conclusion
The study demonstrates a low prevalence of quadrivalent HPV vaccine-targeted genotypes among unvaccinated males aged 16 to 20 in Quebec, reflecting strong herd immunity from the female vaccination program. These findings are critical for informing HPV vaccine schedule evaluations and public health strategies.
References
Brisson et al. 2023 -- HPV Genotype Distribution Among Unvaccinated Males Aged 16 to 20 in Quebec, Canada
