A recent editorial by Simon Barton and Colm O’Mahony in the BMJ highlight real and large declines at the population level of genital warts in both sexes in areas where mass vaccination by the quadrivalent vaccine have been implemented. The authors summarise the achievements to date:
1. A study published by Hammad Ali et al in the same issue reports that survey of of 85 770 new patients from six Australian sexual health clinics show a remarkable reduction in the proportion of women under 21 years of age presenting with genital warts—from 11.5% in 2007 to 0.85% in 2011 (P<0.001). Only 13 cases of genital warts were diagnosed in women under the age of 21 across all six health clinics in 2011. There was no observable effect in women over 30.
2. Interestingly, even though only young women were offered vaccination, there was also a significant decline in genital warts in young men. Between 2007 and 2011 there was a decline of 82% in the prevalence of warts presenting to sexual health clinics in heterosexual men under 21 and 51% in heterosexual men aged 21-30. There were no observed change in prevalence of genital warts in men who have sex with men (MSM). This decline of genital warts in young heterosexual men was thought to be caused to increased herd immunity.
3. Based on these and similar findings and also on grounds of equity the Australian government has begun a publicly funded HPV vaccination program for young men. This aims to reduce the prevalence of genital warts in MSM and also hopefully effect the rising rates of oropharyngeal cancers in men. Ali et al commented that “the vaccination program is expected to increase herd immunity and provide further indirect protection to unvaccinated women” hopefully leading to control, if not elimination of teh targeted HPV types.
4. It is believed that similar falls in HPV-16 and HPV-18 related cancers – such as cervical, anal and oripharyngeal cancers will be reported in the next few years.
5. The editorial expressed the hope that future vaccines will include other potentially harmful HPV types, such as types 31 and 45.