A panel of U.S. experts has recommended federal approval of the first drug shown to prevent HIV — the virus that causes AIDS.

The U.S. Food and Drug Administration advisory panel held two separate votes Thursday on recommending the drug Truvada for healthy people at high risk of AIDS — one for gay and bisexual men and one for heterosexual couples where one person is HIV-positive.

The once-daily pill is already prescribed to many HIV-infected patients. But the FDA must now decide whether to make Truvada the first drug approved for use as a preventative treatment of HIV.

The FDA is under no obligation to follow the panel's recommendation, but usually does. It is expected to make a final decision by June 15.

Some doctors hail Truvada as a step towards the end of the AIDS epidemic. Others say it could give people a false sense of confidence and lead to a reduced use of condoms, the most effective defense against HIV.

Studies show that, when taken as prescribed, Truvada is 90 percent effective at preventing HIV infection. But it was only 44 percent effective among those who used it intermittently.

Some also say that the high cost of the medication, which currently sells for about $14,000 a year, would make it hard to obtain and divert funding from more cost-effective options.