An advisory panel on vaccines at the Centers for Disease Control and Prevention (CDC) in Atlanta has decided not to recommend the human papillomavirus(HPV) vaccine Gardasil for all boys and young men, according to reporting by The Baltimore Sun and The New York Times. Though the panel says the vaccine might be offered to males, the lack of a bona fide recommendation similar to the one in place for girls and young women might mean that government programs won’t cover the cost of the vaccine—and that private insurers might follow suit.

HPV is the primary cause of cervical and anal cancer. It can also cause penile and head and neck cancers. Gardasil protects people against the two strains of HPV responsible for many of these cancers, as well as two other strains that cause genital warts. Just this past month, the U.S. Food and Drug Administration (FDA) approved Gardasil for use in boys and young men who have not yet become sexual. Permission to market the drug is the first hurdle the vaccine had to overcome, the second was gaining a recommendation from the CDC that boys and young men should receive it.

The vaccine panel ultimately decided that the link between HPV and anal and other types of cancers in men was not strong enough and that the prevalence of such cancers was so low in the general public that the vaccine was not cost-effective. While the CDC is not required to act on the recommendations of independent panels, it usually does.

The Baltimore Sun reports that even though the CDC does recommend that girls and young women receive Gardasil to protect against cervical cancer, convincing parents to have their child vaccinated is difficult, and only about one in four girls receives it. In addition, advocates are concerned that the boys who will need protection against HPV won’t be vaccinated unless the CDC gives Gardasil a solid recommendation and insurance companies cover it.

Of particular concern to some advocates is the much higher rate of anal cancer among men who have sex with men (MSM), and especially HIV-positive MSM. Since most MSM become infected with HPV very soon after becoming sexually active, the vaccine would have to be given early in order to be protective. The CDC says it will consider further data on the link between HPV and cancers in men, particularly in MSM, at another meeting in February 2010.

Advocates also argued that boys should be vaccinated as a further means to protect women from infection, but here too the panel felt that this was not a cost-effective way to accomplish this goal. The vaccination involves a series of three shots, and each costs about $130.