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HPV vaccine led to significant declines in genital warts
Significant declines in the number of young women presenting with genital warts in 2011 were attributed to an HPV vaccination program that began in Australia in 2007, according to recent data.
“Provided the HPV vaccination coverage is high enough, dramatic reductions in genital warts can be expected at a population level,” Basil Donovan, MD, professor and head of the Sexual Health Program, The Kirby Institute, at University of New South Wales in Australia, told Infectious Disease News. “Hopefully, this will flow onto similar reductions in ano-genital and oropharyngeal cancers in the future.”
Basil Donovan
Donovan and colleagues collected data from eight sexual health services on 85,770 patients who were seen for the first time from 2004 to 2011. Among these patients, 7,686 had genital warts. In young women aged younger than 21 years, the proportion of women with genital warts declined from 11.5% in 2007 to 0.85% in 2011, a decline of 92.6%. Among women aged 21 to 30 years, the proportion of women with genital warts declined from 11.3% in 2007 to 3.1% in 2011, a decline of 72.6%. There was no decline in genital warts incidence seen among women aged older than 30 years.
There also was a decline in genital warts incidence in heterosexual young men. Among those aged younger than 21 years, the proportion of those with genital warts declined from 12.1% in 2007 to 2.2% in 2011, a decline of 81.8%. Among those aged 21 to 30 years, the proportion of those with genital warts declined from 18.2% in 2007 to 8.9% in 2011, a decline of 41.1%. There was no decline observed for men aged older than 30 years.
Donovan said there were three surprising results about this study: 1) the indication that the herd immunity effect in young heterosexual men seems to be intensifying; 2) there is a nonsignificant suggestion that the herd immunity in men is beginning to protect unvaccinated women; 3) the complete disappearance of genital warts in vaccinated women, even sometimes in partially vaccinated women.
“Traditionally, we have been told that about 90% of genital warts are caused by HPV types 6 and 11, but our data suggest that these HPV types may be responsible for all or almost all genital warts,” Donovan said.
He said future research will involve determining the effects of adding males to the HPV vaccination program.
Basil Donovan, MD, can be reached at Sexual Health Program, The Kirby Institute, University of New South Wales, Sydney NSW 2052, Australia; email: bdonovan@kirby.unsw.edu.au.
Disclosure: The researchers report financial relationships with CSL Biotherapies, Merck and Sanofi-Pasteur.