A Food and Drug advisory committee voted 13-0 on five separate times to endorse Merck and Co.'s Gardasil. The anticipated cost of the vaccine, administered in three shots over six months, is $300 to $500 — a possible impediment to widespread vaccination campaigns.

The drug protects against the two types of human papillomavirus (HPV) believed responsible for about 70 percent of cervical cancer cases. The vaccine also protects against two other virus types that cause 90 percent of genital wart cases. All four virus types are sexually transmitted.

The FDA is not required to follow the recommendations of its outside panels of experts, but usually does. An agency decision is expected by June 8.