Vaccine against cervical cancer and genital warts looks hopeful

More than two thirds of sexually active women will become infected with human papillomavirus (HPV) during their lifetime. HPV causes around 470 000 cases of cervical cancer each year and even though most cases of cervical cancer occur in the developing world, where cervical screening programmes are in the main non-existent, in Europe and the US 35000 women die from the disease every year.

HPV is also responsible for genital warts in 1–2% of young adults which can cause sexual dysfunction, keeps recurring and treatment is painful and expensive. A vaccine against the virus could reduce persistent infection and disease by 90%, suggest the results of a randomised trial by Luisa Villa (Ludwig Institute for Cancer Research, Brazil) and colleagues.

The trial tested the effectiveness of a vaccine targeting the HPV types associated with cervical cancers genital warts. They recruited 1158 healthy women aged 16-23 onto the study from Brazil, Europe and the USA. The participants were not pregnant, had no previous abnormal cervical smears and reported a history of four or fewer partners. 277 women were randomly assigned to the vaccine and 275 to a placebo. They were given intramuscular injections on day 1, month 2 and month 6. Participants were followed up for 36 months and underwent regular gynaecological examinations, sampling for HPV DNA and cervical smears.

The incidence of persistent infection or disease with HPV 6, 11, 16, or 18 fell by 90% in those assigned the vaccine compared with those assigned the placebo. The vaccine was 100% effective against precancerous cervical lesions and genital warts associated with these four HPV types. There were no serious side effects.

The researchers suggest that universal HPV vaccination might be most effective if given to 10–13 year olds, who are likely to be HPV negative. Large-scale trials of the vaccine are currently underway.

Dr Villa concludes that screening for cervical-cancer in the developed world has substantially shifted the burden of HPV infection from cervical cancer mortality to management of precancerous lesions. In these countries, in addition to a further reduction in the incidence of cervical cancer, universal HPV vaccination might decrease the medical, psychological, and economic costs associated with the management of abnormalities detected by screening. Inclusion of HPV 6 and 11 in a vaccine could also diminish the incidence of genital warts. In developing countries that have not implemented screening programmes for cervical cancer, a universal HPV vaccine could substantially reduce the incidence of the disease.

The research is reported in the current issue of The Lancet Oncology.