The Food and Drug Administration on Friday approved Merck & Co.’s cervical cancer vaccine Gardasil to prevent vulvar and vaginal cancers.

In 2006, FDA gave its approval for Gardasil use in girls and women aged 9-26 to prevent infections with four strains of the human papillomavirus, or HPV, which causes most genital warts and cervical cancers. There are over 100 different strains of the human papillomavirus and about 40 of them trigger to genital infections. Of those 40, about half can cause cancer. The vaccine is efficient only regarding the prevention of four types of the virus that may lead to 90 percent of genital warts and 70 of cervical cancer. Two of those HPV strains can also cause some vulvar and vaginal cancers. 

The CDC recommends Gardasil for all girls aged 11-12, as most girls of this age are not yet sexually active and will achieve a maximum protection. Girls can get Gardasil when they’re as young as 9. A recent study carried out by the Harvard School of Public Health concluded that, if the vaccine is administered to females before they become sexually active, the measure proves very cost-effective in terms of preventing the cancer.

The cancers of the vagina and the vulva affect more than 5,000 women annually in the United States, according to Merck.

The study carried out by Merck, which followed more than 15,000 women from its earlier cervical cancer studies for an additional two years concluded that none of the vaccinated women developed HPV-related precancers in the vagina or vulva. But the benefits were seen only in women who hadn’t been infected with HPV before getting the vaccine.

“There is now strong evidence showing that this vaccine can help prevent vulvar and vaginal cancers due to the same viruses for which it also helps protect against cervical cancer,” Jesse L. Goodman, MD, MPH, director of the FDA’s Center for Biologics Evaluation and Research, says in a news release.