"FDA approval of the HPV vaccine, the first vaccine targeted specifically to preventing cancer, is one of the most important advances in women's health in recent years," states the American Cancer Society in a news release.
The vaccine protects against infection from four strains of the human papilloma virus, or HPV. Two of these strains, HPV-16 and HPV-18, account for about 70 percent of cervical cancers. The other two strains covered by the vaccine, HPV- 6 and HPV-11, account for about 90 percent of genital warts.
"Gardasil is a major health breakthrough -- the first vaccine specifically designed to prevent cancer -- and is approved to prevent not only cervical cancer but also genital warts," says Kevin Ault, MD, leader of Gardasil clinical trials at Atlanta's Emory University, in a Merck news release.
The vaccine is approved for 9- to 26-year-old girls and women. While it is almost always females who get HPV-related cancer, the virus is spread by both men and women during sexual contact. And both men and women are susceptible to genital and rectal warts, which can lead to cervical changes and abnormal Pap smears in women.
Gardasil is not approved for use by boys and men. Clinical trials evaluating Gardasil vaccination of boys and men are underway, a Merck spokesperson tells WebMD.
Effective and Safe
In clinical trials reported so far, the vaccine has been extremely effective. It appears to be 100 percent effective in protecting against the HPV-16 and HPV-18 strains. It also seems extremely safe. One reason is that the vaccine isn't a live virus, but a virus-like particle. This means it's an empty shell, with immunity-stimulating particles on the outside and no viral machinery on the inside.
HPV expert Jessica Kahn M.D., MPH, associate professor of pediatrics at Cincinnati Children's Hospital Medical Center, says she's planning to have her teenage daughter vaccinated.
"What we parents most want to know about the vaccine is whether it is safe, and whether it is effective," Kahn tells WebMD. "All data show it to be one of the safest vaccines ever tested. And it is highly effective."
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.