Genital Warts Decline Thanks to HPV Vaccine

A new study reveals that the incidence of genital warts declined by more than 90% in adolescent and teenage girls following the introduction of the human papillomavirus (HPV) vaccine in Australia.

Researchers at the University of New South Wales (Sydney, Australia), the University of Melbourne (Australia), and other institutions conducted a trend analysis study of surveillance data involving 85,770 Australian born patients to measure the effect on genital warts of the national HPV vaccination program in Australia, which started in mid-2007. Data were collated from eight sexual health services from 2004 to 2011, with the two largest clinics also collecting self-reported HPV vaccination status from 2009. The main outcome measure was trends in proportion of new patients diagnosed as having genital warts.

The results showed that large declines occurred in the proportions of women diagnosed as having genital warts in the vaccination period—from 11.5% in 2007 to 0.85% in 2011 in women under 21, and from 11.3% in 2007 to 3.1% in 2011 in women 21–30; no significant decline in wart diagnoses was seen in women over 30 years of age. Significant declines also occurred in proportions of under 21 year old and 21–30 year old heterosexual men diagnosed as having genital warts; again, no significant decline in genital wart diagnoses was seen in heterosexual men over 30 years of age. Significantly, in 2011 no genital wart diagnoses were made among 235 women under 21 years of age who reported prior HPV vaccination. The study was published in April 18, 2013, in BMJ.

“The significant declines in the proportion of young women found to have genital warts and the absence of genital warts in vaccinated women in 2011 suggests that the human papillomavirus vaccine has high efficacy outside the trial setting,” concluded lead author Basil Donovan, MD, of the University of New South Wales, and colleagues. “Large declines in diagnoses of genital warts in heterosexual men are probably due to herd immunity.”

In 2007 Australia became one of the first countries to implement a nationally funded program of HPV vaccination, offering free vaccination to girls aged 12–13 years in schools. In addition, from 2007 to 2009 two catch-up programs were implemented, one for 13–18 year old schoolgirls and the other for 18–26 year old women in the community. The quadrivalent vaccine provides protection against HPV types 6 and 11, which cause genital warts, in addition to the cancer causing types 16 and 18.

Related Links:
University of New South Wales
University of Melbourne