Background:
Human papillomavirus (HPV) is associated with several cancers, especially cervical cancer. A publicly-funded HPV vaccination program targeting 12-13 year old females commenced in Australia in 2007, with catch-up of females 13-26 years to 2009. Indigenous females in Australia are at higher risk of cervical cancer, but analyses of vaccine impact have not previously been reported according to Indigenous status. Vaccination potentially impacts cervical abnormalities and genital warts but Indigenous status is not recorded on registers of cervical abnormalities.
Aim:
To examine the impact of HPV vaccination in Australia, using genital warts as an early outcome measure, including by Indigenous status.
Methods:
We analysed data from a comprehensive national dataset (the Australian National Hospital Morbidity Database) of all hospital admissions between 1999 - 2011 coded as involving a diagnosis of genital warts
Results:
Admission rates decreased from mid-2007 in females aged 12-17 years (annual decline 44.1%; 95% CI: 35.4-51.6%), and from mid-2008 in both females and males aged 18-26 years (annual decline 31.8%; 95% CI: 28.4-35.2% and 14.0%; 95% CI: 5.1-22.1% respectively. The overall observed reductions in 2010/2011, compared to 2006/2007, were 89.9% (95%CI:84.4-93.4%) for females aged 12-17 years, 72.7%(95%CI:67.0-77.5%) for females aged 18-26 years and 38.3% (95%CI:27.7-47.2%) for males aged 18-26 years. Post-vaccination reductions were similar for Indigenous (86.7%; 95%CI:76.0-92.7) and other Australian females (76.1%; 95% CI:71.6-79.9%) aged 15-24 years (Pheterogeneity=0.08).
Conclusions: We observed a marked decline in hospital admissions involving a diagnosis of genital warts in young people in Australia after 2007. These population-based findings confirm results from previous studies, including indirect benefits to males from the female vaccination program. The impact of HPV vaccination in young Indigenous females appears similar to that in non-Indigenous females. In the long term, HPV vaccination may contribute to closing the gap in cervical cancer between Indigenous and non-Indigenous females.