Vaccine to prevent cervical
cancer approved
The Food and Drug Administration recently approved a vaccine called Gardasil to protect women against cervical cancer, after a 40-month trial of 4,000 young women at 13 U.S. sites, including Vanderbilt University Medical Center.
The vaccine works by preventing infection from four strains of the human papillomavirus, (HPV), the most common sexually transmitted disease. About 20 million people are believed to be infected with HPV, according to the National Institute of Allergy and Infectious Diseases.
Gardasil protects against Types 16 and 18, the two strains of HPV responsible for about 70 percent of cervical cancer cases. Although many women are infected with HPV, their normal immune defense system fights the virus, and most women never go on to have an abnormal Pap smear or cervical cancer. The vaccine boosts this natural immunity, and in turn, may prevent the viral infection and help women whose immune systems don't fight the virus. The vaccine also blocks infection of two other strains of HPV, responsible for 90 percent of genital warts cases.
"Over the past 15 years, there has been increasingly clear evidence that cancer of the cervix is caused by a virus," said Howard Jones III, M.D., director of Gynecologic Oncology at Vanderbilt-Ingram and one of the study's investigators. "We've been able to identify over time that
it's the HPV virus that causes cervical cancer, but
we've never been able to prevent it. This vaccine allows us, for the first time, to prevent the infection of HPV in women."
Jones said the next step is to see if the vaccine works in the general population, to make sure there are no side effects, and that it's effective in larger groups of people. "But it is still important that women continue to get their regular Pap smear screening. Even if everyone is being vaccinated 15 years from now, we still might have 30 percent of the current number of women with cervical cancer because the current vaccine is directed against only the two most common types of HPV which cause 70 percent of cervical cancer. In addition, the progression from HPV infection to cervical cancer is slow, and women may already be infected but not develop an abnormal Pap smear for several years."
The vaccine is costly – about $360 for the three required doses spread over four months. It has been approved for girls and young women, 9 to 26, who test negative for the virus and do not have cervical dysplasia.
The Vanderbilt portion of the study was led by principal investigator Peter Wright, M.D., professor of Pediatrics, Microbiology and Immunology and Pathology, and director of the Division of Pediatric Infectious Disease. Fifty-one young women between the ages of 16 and 26 were enrolled locally, mostly Vanderbilt undergraduate students who were recruited by John Greene, M.D., director of the Zerfoss Student Health Center.
- by Nancy Humphrey
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