Cervical Cancer Vaccine Approved
FDA Approves Gardasil for Girls and Women Aged 9-26
Effective and Safe continued...
To be effective, Gardasil must be given in three doses over six months (the second dose is given two months after the first; the third dose six months after the first). It's not yet clear whether a person will receive lifelong immunity. In tests checking for presence of the virus so far, the vaccines remain protective for four years and counting. For preventing vaginal and vulvar cancer, the vaccines have been protective for at least two years.
The wholesale price for Gardasil will be $120 per dose; $360 for all three doses.
There's a second vaccine in the works: Cervarix, from GlaxoSmithKline. Cervarix targets only two HPV strains, HPV-16 and HPV-18, the ones most commonly linked to cancer as opposed to genital warts. GlaxoSmithKline says it plans to seek FDA approval for Cervarix by the end of the year. Early studies find that this vaccine, too, is extremely safe and effective.
Both Merck and GlaxoSmithKline are WebMD sponsors.
Pap Screening Still Needed
Despite its potency, Gardasil won't prevent every cervical cancer cervical cancer or every HPV infection. There are some 100 HPV strains out there. Those covered by the vaccine are the worst offenders, but not the only ones.
Neither Gardasil nor Cervarix prevent disease in people already infected with the virus. Perhaps as many as 80% of adults have been exposed to at least one strain of HPV, Kahn says. For reasons not fully understood, only a minority of people with HPV get cervical cancercancer or wartswarts.
"These vaccines only prevent infection. They do not prevent disease once you are already infected with the virus," Kahn says. "The vaccines do not treat precancerous conditions."
This means that while the vaccines undoubtedly will prevent many of the annual 3,700 U.S. and 233,000 worldwide cervical-cancer deaths, it will not end cervical cancer, genital wartsgenital warts, or the spread of other HPVs.
"One of the points I am going to try to get across to teens is to stressstress that even after getting the vaccine, they must continue to get regular Pap screening," Kahn says. "Some vaccinated women will still have abnormal Pap tests. It does not mean the vaccine is not working. A lot of abnormal Paps are caused by HPVs that are not in the vaccines."