Final analysis of a study assessing genital human papillomavirus genoprevalence in young Australian women, following eight years of a national vaccination program.

OBJECTIVES

The VACCINE [Vaccine Against Cervical Cancer Impact and Effectiveness] study evaluated the prevalence of quadrivalent vaccine-targeted human papillomavirus (HPV) genotypes (HPV 6, 11, 16, 18) amongst young women of vaccine-eligible age.

METHODS

Between October 2011 - June 2015, women aged 18-25 years from Victoria, Australia, were recruited through targeted advertising on the social networking website Facebook. Participants completed an online questionnaire and provided a self-collected vaginal swab for HPV DNA detection and genotyping (Linear Array HPV genotyping assay). Self-reported HPV vaccination details were verified with the National HPV Vaccination Program Register (NHVPR).

RESULTS

Of 1223 who agreed to participate, 916 (74.9%) completed the survey and, for 1007 (82.3%) sexually-active participants, 744 (73.9%) returned the self-collected swab, of which 737 contained detectable DNA. 184/737 (25.0%) were positive for HPV. Vaccine-targeted HPV genotypes were detected in only 13 (1.7%) women: 11 HPV 16 (six vaccinated after sexual debut, five unvaccinated) and two HPV 6. Prevalence of any of HPV 31/33/45 collectively was 2.9%, varying significantly by vaccination status (fully 2.0%, unvaccinated 6.8%; p = 0.01). Vaccination rates among the sexually-active cohort were high, with 65.6%, 71.6% and 74.2% of participants having received three, at least two or at least one dose of vaccine, respectively. Of women self-reporting HPV vaccination, the NHVPR confirmed one or more doses were received in 90%. Strong associations were observed between vaccination status, age, language spoken at home and country of birth, as well as between HPV detection and the number of male sexual partners.

CONCLUSION

Surveillance five to eight years' post-initiation of a national HPV vaccination program demonstrated a consistent and very low prevalence of vaccine-related HPV genotypes and some evidence of cross protection against related types amongst vaccine-eligible women from Victoria, Australia.