Vaccination for cervical cancer less effective in 'sexually active'

Merck`s Gardasil, a vaccine for cervical cancer, has proved to be less effective in women who have been infected with human papillomavirus (HPV) in the past. HPV is one of the chief causes for cervical cancer. In other words, the vaccine has not been able to work wonders for women who are sexually active.

"It's important that women understand if they're sexually active, there's a chance they won't receive full benefit from the vaccine", says Laura Koutsky, an epidemiologist with the University of Washington.

The results of the nationwide study of the vaccine will be published in the May 9 issue of the New England Journal of Medicine. The study showed that 93% of the women, between the age groups of 15 to 26, who participated in the study, were sexually active.

Strains of the sexually transmitted HPV which infects one in four women in the U.S are the culprit behind 70% of cervical cancer cases and 90% of genital warts cases. It has been estimated that 20 million people in America are infected with some form of HPV.

According to Koutsky, most of the virus disappears after a while. This protects them against any future attack by the same strain. For cases where the virus lasts for a long time, chances of cervical cancer increase manifold. Gardasil, like any other drug, proves less effective in cases where the patient has already been infected with the virus.

Gynaecologist Kevin Ault says, "Just like any vaccine, it's not going to be effective in people who already have the disease".

The Centres for Disease Control and Prevention have recommended vaccination of girls between the ages of 9 and 11. A controversial order passed by the Texas governor which requires vaccinating girls against HPV before they enter sixth standard, has raised quite a furore. The bill makes the shots a voluntary precaution to protect against cervical cancer.

According to the American Cancer Society, around 11,150 cases of cervical cancer are expected to be diagnosed in the US in 2007 and 3,670 women are expected to die of the disease this year.

The study which was purely conducted on women showed that Merck’s new drug would have a great benefit for young women. As was reaffirmed by Dr. Richard Haupt, director of medical affairs in Merck’s vaccine division.