Merck's Vaccine Victory Not Yet Complete

Still, Gardasil may face challenges from religious organizations that say the best defense against HPV is abstinence. Some critics of the drug have said the vaccine could promote promiscuity.

Liddon, at the ACIP meeting, said that claim "is not a new concept." Previously, she said, warnings have been issued about, among other things, the "increased sexual risk if penicillin were used to treat syphilis." Various studies suggest that promiscuity "will be unlikely to result" from HPV vaccinations, Liddon said.

In recent months, some organizations have issued formal statements saying that they don't oppose HPV vaccines, but they also don't want them required for school attendance. The ACIP will review recommendations that Gardasil be provided routinely for girls as young as 11.

One such group, Focus on the Family, says it "supports widespread availability of HPV vaccines but opposes mandatory vaccinations for entry to public school." The Colorado-based group says any decision for vaccinating a child against an STD "should remain with the child's parent or guardian." The best protection against HPV, it says, is abstinence before marriage and faithfulness afterward.

Merck's public response to potential critics has been cautious.

"Support continues to grow" for Gardasil, says spokeswoman Kelley Dougherty, adding that the company will "work with stakeholders" to provide education about HPV and vaccination. Merck provides disease and vaccine information to state health departments, and it will offer Gardasil information after the ACIP vote, she says.

Assuming there's a favorable ACIP vote, Dougherty adds, it would be hard to predict how quickly states would act because each has different public health procedures.