Human Papillomavirus (HPV) Vaccine Effectiveness and Potential Herd Immunity for Reducing Oncogenic Oropharyngeal HPV-16 Prevalence in the United Kingdom: A Cross-sectional Study.

BACKGROUND: Oropharyngeal cancer incidence is rapidly rising due to human papillomavirus (HPV) type 16 infection. The dearth of data on effectiveness of national female-only vaccination programs in preventing oral HPV infection and potential herd immunity in unvaccinated males has resulted in considerable controversy regarding the need to vaccinate males, especially in countries with high female vaccination coverage. METHODS: Subjects aged 0-65 years undergoing tonsillectomy for nonmalignant indications were recruited in 6 hospitals in the United Kingdom. Oral samples were collected as follows: oral rinse, tongue base, and pharyngeal wall brushes, then tonsil tissue (tonsillectomy). Vaccination data were obtained from regional health authorities. All samples were centrally tested for HPV DNA by polymerase chain reaction. RESULTS: Of 940 subjects, 243 females and 69 males were aged 12-24 years (median age, 18.6 years), with 189 (78%) females and no males vaccinated against HPV. Overall, oropharyngeal HPV-16 prevalence was significantly lower in vaccinated versus unvaccinated females (0.5% vs 5.6%, P = .04). In contrast, prevalence of any oropharyngeal HPV type was similar in vaccinated and unvaccinated females (19% vs 20%, P = .76). Oropharyngeal HPV-16 prevalence in unvaccinated males was similar to vaccinated females (0% vs 0.5%, P > .99), and lower than unvaccinated females (0% vs 5.6%, P = .08). CONCLUSIONS: Our findings indicate that the UK female-only vaccination program is associated with significant reductions in oropharyngeal HPV-16 infections. These are also the first data to suggest potential herd immunity from female-only vaccination against oropharyngeal HPV infection in contemporaneously aged males.