Fall in Human Papillomavirus Prevalence Following a National Vaccination Program

Abstract

In April 2007, Australia became the first country to introduce a national government-funded human papillomavirus (HPV) vaccination program. We evaluated the program's impact on genotype-specific HPV infection prevalence through a repeat survey of women attending clinical services. HPV genoprevalence in women aged 18-24 years attending family planning clinics in the prevaccine period (2005-2007) was compared with prevalence among women of the same age group in the postvaccine period (2010-2011). The same recruitment and testing strategies were utilized for both sets of samples, and comparisons were adjusted for potentially confounding variables. The prevalence of vaccine HPV genotypes (6, 11, 16, and 18) was significantly lower in the postvaccine sample than in the prevaccine sample (6.7% vs 28.7%; P < .001), with lower prevalence observed in both vaccinated and unvaccinated women compared with the prevaccine population (5.0% [adjusted odds ratio, 0.11; 95% confidence interval, 0.06-0.21] and 15.8% [adjusted odds ratio, 0.42; 95% confidence interval, 0.19-0.93], respectively). A slightly lower prevalence of nonvaccine oncogenic HPV genotypes was also found in vaccinated women (30.8% vs 37.6%; adjusted odds ratio, 0.68; 95% confidence interval, 0.46-0.99). Four years after the commencement of the Australian HPV vaccination program, a substantial decrease in vaccine-targeted genotypes is evident and should, in time, translate into reductions in HPV-related lesions.