Abstract

Objective: Our aim was to determine if the Australian human papillomavirus (HPV) vaccination program has had a population impact on presentations of genital warts.

Methods: Retrospective study comparing the proportion of new clients with genital warts attending Melbourne Sexual Health Centre (MSHC) from January 2004 to December 2008. Australia provided free quadrivalent HPV vaccine to 12-18 year old girls in a school-based program from April 2007, and to women ≤26 years through general practices from July 2007.

Results: 36,055 new clients attended MSHC between 2004-2008 and genital warts were diagnosed in 3,826 (10.6%; 95% CI: 10.3-10.9). The proportion of women <28 years with warts diagnosed decreased by 25.1% (95% confidence interval (CI) 30.5%,19.3%) per quarter in 2008. Comparing this to a negligible increase of 1.8% (95% CI 0.2%,3.4%) per quarter from the start of 2004 to the end of 2007 also in women < 28 years generates strong evidence of a difference in these two trends (p < 0.001). There was no evidence of a difference in trend for the quarterly proportions before and after the end of 2007 for any other subgroup, and on only one occasion was there strong evidence of a trend different to zero, for heterosexual men in 2008 where the average quarterly change was a decrease of 5% (95% CI (0.5%,9.4%), p = 0.031).

Conclusions: Our data suggest a rapid and marked reduction in the incidence of genital warts among vaccinated women may be achievable through an HPV vaccination program targeting women, and supports some benefit being conferred to heterosexual men.