Vaccine for HPV-16 Prevents Cervical Cancer

A study has found a new vaccine to be safe and effective in preventing infection of human papillomavirus type 16 (HPV-16), a common virus causing about half of all cases of cervical cancer. The study was published in the November 21, 2002, issue of The New England Journal of Medicine.

Researchers in the study followed women 2,400 women 16-32 years old at 16 US centers for two years. They found that the incidence of HPV-16 infection was 3.8 per 100 woman-years at risk among women who received a placebo versus none per 100 woman-years at risk among women who received the vaccine. The researchers expect to follow the women for two more years. The current results were based on the outcomes of 1,533 women. A total of 41 women in the placebo group tested positive for HPV-16 during the study, and nine women in the group were found to have HPV-16-related cervical intraepithelial neoplasia. No cases of HPV-16 infection or neoplasia occurred among the women who received the vaccine.

The researchers say the vaccine appears to prevent HPV from lingering in the genital tract where, in addition to causing a lesion, it can be transmitted to a sex partner. Cervical intraepithelial neoplasia is a precancerous lesion of the cervix that may linger before turning into invasive cancer or may disappear.

"These are very promising results, but the bottom line is that until a vaccine is fully tested and available, the best way to prevent cervical cancer is to participate in routine Pap screening,” said Dr. Laura Koutsky, professor of epidemiology at the University of Washington's School of Public Health and Community Medicine (Seattle, USA), and principal investigator of the study.

Investigators are currently enrolling women in a study of a vaccine that targets four types of HPV. This combined vaccine targets two HPV types that cause about 70% of cervical cancers and two HPV types that cause about 90% of genital warts. The vaccines are being developed by Merck Research Laboratories, a unit of Merck & Company (NY, NY, USA).




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