Cervical Cancer

A Vaccine to Wipe Out Cervical Cancer

It may be another year or two before a vaccine for cervical cancer is available, but pediatricians are already expressing an interest in providing it to adolescents who are not yet sexually active. The vaccine works by preventing infection with the human papillomavirus (HPV), a common sexually transmitted disease (STD) that causes most cases of cervical cancer.

Excitement for the vaccine has been building since researchers announced that one early version, called Gardasil, was 100 percent effective in blocking HPV infection. But the vaccine raises a difficult issue for parents. Would inoculating adolescents against an STD promote unsafe sex?

This question will need to be answered soon. If the dramatic results hold up in further testing, the HPV vaccine may be available as early as 2006. In the meantime, researchers took pause to rejoice in the recent good news.

"There's almost nothing that's 100 percent in medicine," says study author Dr. Kevin Ault, assistant professor of obstetrics and gynecology at Emory University School of Medicine. "It's pretty exciting."

The End of Cervical Cancer?
Dr. Eliav Barr, senior director of Clinical Research at Merck Research Laboratories, explained that Gardasil was designed to target the two types of HPV most commonly associated with cervical cancer, as well as the types that cause genital warts and many abnormal Pap smears. Barr said his hope was "to reduce the burden from HPV-related diseases as much as possible."

The study on Gardasil, presented at a meeting of the Infectious Diseases Society of America this October, included an international group of over 12,000 sexually active women between the ages of 16 and 26. Half received three doses of the HPV vaccine, and the other half received placebo shots.

After seven months, those who were virus-free were followed for an additional 17 months. In this group, none of the women who were vaccinated developed either cervical cancer or precancerous lesions in their cervix, while 21 of the women in the placebo group did. This shows that the vaccine is 100 percent effective when all doses are administered before a woman contracts HPV.

In a follow-up, the researchers expanded their analysis to include all women who were virus free after only the first dose of the vaccine. This left room for those who may have contracted HPV before the end of the vaccination cycle to be included in the final tally—making the results more realistic, according to the researchers.

In this later analysis, only one woman in the vaccinated group was found to have precancerous growths, while 36 of the unvaccinated women had developed either precancerous growths or cervical cancer. In this more "real world" sample, the risk of developing precancerous growths was reduced by 97 percent after taking Gardasil.

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