Gynecologists and pediatricians largely supported a U.S. Food and Drug Administration advisory panel's vote on Wednesday to approve the vaccine Gardasil for use in males aged 9-26 to protect against genital warts. But some say a conservative approach should be taken in vaccinating boys until more evidence is in.
The panel's recommendation on Gardasil and males comes just weeks after research in the New England Journal of Medicine raised questions about the lack of clear-cut evidence that a vaccine for cervical cancer is effective. Other studies have raised questions about serious side effects from HPV vaccines like Gardasil.
The votes are non-binding, but the FDA usually follows an expert panel's advice.
Merck, the company that manufactures the vaccine, which protects against four common strains of the human papilloma virus (HPV) and has been approved to prevent genital lesions and cervical cancer in women, has consistently presented strong evidence supporting the vaccine's efficacy in males.
But lacking key information about the vaccine's duration and potential to protect against cancer in males, experts are adopting a wait-and-see attitude towards the drug until the FDA and some professional societies make formal recommendations for Gardasil use.
"[The data] looked very convincing so I wasn't really surprised that the recommendation was favorable," said Dr. Kevin Ault, associate professor of Gynecology and Obstetrics at Emory University. "It's true that [genital warts] are not cancer but they're difficult to treat and socially stigmatizing. That might be a trigger for more widespread use."
ABC News' Chief Medical Editor Dr. Timothy Johnson said he favored a conservative approach in light of the panel's recommendation.
"It's going to be a really tough choice for parents and they should make that decision on a family basis," Johnson said. "I'm not prepared to say all boys in that age group should get it without question."
One of the goals for vaccinating males was the potential to reduce HPV transmission to females. In the U.S., 6.2 million cases of HPV are diagnosed each year in men and women, according to the Centers for Disease Control and Prevention.
"The HPV virus doesn't spring from the air to the genitals of males and females, boys and girls. They are spreading it to each other," said Dr. Joseph Zanga, chief of Pediatrics at Columbus Regional Healthcare System. "We should try our best to protect them from inconvenient and potentially very dangerous diseases... But if it doesn't do that, then it will be useful in preventing an infection for boys but won't help girls."
But preventing men from HPV infections that could lead to head and neck, anal, and penile cancers -- those being the most common HPV-related cancers in men -- could be appealing, particularly since there is no infrastructure for regular screening of such cancers the way that regular pap smears have helped prevent cervical cancer in women.
"It's under-recognized how important HPV is as a disease causing infection in men," said Dr. Richard M. Haupt, head of the clinical program for Gardasil at Merck.
But no data shows that Gardasil offers direct protection against cancer. Instead, the vaccine has the potential to be protective based on its ability to prevent the persistent HPV infections that can be precursors to cancer.