Who Will Benefit From Expanding HPV Vaccination Programs to Boys?

Indications for human papillomavirus vaccination programs are expanding to boys. However, the rationale behind their inclusion is often not clear. Using a Bayesian synthesis framework and assuming equal vaccine coverage in both sexes, we assessed how the incremental number of cancer cases prevented and life-years gained from boys' vaccination are distributed between women, heterosexual men, and men who have sex with men (MSM). Below 60% coverage, at least 50% of the gains from boys' vaccination was attributable to cervical cancer prevention, whereas at 80% coverage, 50% of the gains was attributable to women, 15% to heterosexual men, and 35% to MSM. Above 90% coverage, 85-100% of the gains from boys' vaccination was attributable to anal and oropharyngeal cancer prevention, mainly in MSM. Sex-neutral vaccination can be advocated on grounds of bolstering herd protection to women and directly protecting men, particularly MSM, with the clinical significance of either argument determined by the coverage.