Healthy people at risk for HIV are advised to take daily pills that cut the odds of infection by more than 90 percent, U.S. health officials said Wednesday in the first formal recommendation on using the drugs as a preventive.

The group urged to take the pills includes people with HIV-infected partners and those who inject illicit drugs and share equipment, or have been in treatment programs for injection medicine use, the Centers for Disease Control and Prevention said in a statement. Gilead Sciences’ anti-AIDS pill Truvada has been approved as a preventive medicine for the virus that causes AIDS.

Also advised to take the medicines are heterosexual men or women who don’t always use condoms with at-risk partners and gay or bisexual men who have sex without a condom or are not in mutually exclusive relationships with partners testing HIV-negative, the agency said.

For HIV, “there’s no vaccine and cure in the near horizon. Prevention is key,” said Jonathan Mermin, director of the CDC’s national center for HIV/AIDSprevention.

PrEP, or pre-exposure prophylaxis, is a step toward combating the AIDS-causing virus that infects 50,000 new patients each year in the United States. Gilead’s Truvada was approved for sale by the Food and Drug Administration in 2012 to be used as part of a prevention strategy that included safe sex practices and regular HIV testing.