Australasian Science: Australia's authority on science since 1938

Gen Y Says Bye to Genital Warts

By Stephen Luntz

Genital warts are becoming a thing of the past among younger Australians as a by-product of cervical cancer vaccination.

Strains 16 and 18 of the human papillomavirus (HPV) cause the majority of cases of cervical cancer. Genital warts are most frequently a result of strains 6 and 11, so the Gardasil vaccine, based on the work of former Australian of the Year Prof Ian Frazer (AS, April 2006, p.9), was designed to protect against all four.

Cervical cancer takes a long time to show up so warts provide a good way to track the vaccine’s success.

Dr Tim Read of the Melbourne Sexual Health Centre says genital warts are more than a nuisance. “As a physician in a sexual health centre I used to keep a bottle of liquid nitrogen on my desk and could guarantee to have to remove warts several times a day,” he says. Cryotherapy did not always work, and in some cases “the treatment was worse than the disease” – as well as often being expensive.

Many treatments are considered unsafe for pregnant women, and in rare cases the warts are transmitted to children during birth – with serious consequences.

Australia has one of the most comprehensive HPV vaccination programs in the world, producing ideal conditions for Read, along with colleagues at the Kirby Institute, to study diagnoses for 85,770 visitors to sexual health clinics in Australia between 2004 and 2011. The results are now published in the British Medical Journal.

Reporting of warts by women under the age of 21 plunged from 11.5% (and rising) in 2007 to 0.85% in 2011. Among women aged 21–30 it fell from 11.3% to 3.1%, but older women have experienced a statistically insignificant rise.

Younger heterosexual men have also seen substantial falls in wart occurrence. Since male mass vaccination is only just beginning, Read attributes this to the men being protected by vaccinated partners.

HPV is also associated with a range of other cancers, most notably anal cancers among gay men. It is hoped the vaccine’s extension to boys will produce benefits in years to come, although Read says: “I’ll be retired by the time anal HPV cancers are wiped out”.

Gardasil is a particularly expensive vaccine, leading some to question its value for money, but Read says on the basis of his research “it might just pay its way”. Meanwhile the liquid nitrogen on his desk can often go unused for days.