Effectiveness of Human Papillomavirus Vaccination on Prevalence of Vaccine Genotypes in Young Sexually Active Women in France.

Background. Effectiveness of human papillomavirus (HPV) vaccines in the context of both guidelines, which recommend vaccination at 14 years and modest vaccine coverage, is poorly documented. Methods. Residual specimens from females aged <25 years undergoing chlamydia testing were collected, together with demographic, sexual behavior, and vaccine status data. Human pappilomavirus genotypes were determined using the PapilloCheck test system. We compared vaccine type (VT; types 6, 11, 16, 18) prevalence according to vaccination status and identified factors associated with VT prevalence. Results. Of 3736 eligible samples, 822 were from vaccinated women according to immunization record, 1021 from women self-reporting vaccination, and 1893 from unvaccinated women. Adjusted vaccine effectiveness for confirmed vaccinated compared with unvaccinated women was 95.93% (95% confidence interval [CI] = 90.22-98.32) against VT HPV and 38.37% (95% CI = 12.68-56.51) against cross-reactive genotypes (HPV 31, 33, 45), respectively. Vaccine type HPV prevalence was significantly lower (0.61%) among confirmed-vaccinated women than among those who self-reported vaccination or unvaccinated women (1.76% and 15.0%, respectively). Factors associated with prevalent VT in multivariable analysis were vaccine status, positive Chlamydia trachomatis and >= 4 partners in the preceding year. Conclusion. Our study demonstrates evidence of high effectiveness of HPV prophylactic vaccines at an individual level, supporting that wider implementation will help to reduce cervical cancer and precursors incidence.