A sizeable percent of gay American men and injection drug users are at substantial risk of HIV and should take a powerful, preventative drug to help avoid infection, American health officials said.
Taking pre-exposure prophylaxis (PrEP) daily can drastically reduce the risk of HIV infection, but the treatment is currently under-prescribed, the US Centers for Disease Control and Prevention said late Tuesday.
A quarter of gay and bisexual men and 20 percent of adults who inject drugs are at substantial risk of contracting HIV and should be counseled about taking PrEP, the CDC said.
The less than one percent of heterosexually active adults in the same risk category should be advised as well, it added.
"PrEP isn't reaching many people who could benefit from it, and many providers remain unaware of its promise," said CDC Director Tom Frieden.
The drug can reduce risk of infection among gay and bisexual males by more than 90 percent and among injection drug users by more than 70 percent, according to the CDC.
"With about 40,000 HIV infections newly diagnosed each year in the US, we need to use all available prevention strategies," Frieden said.
The US Food and Drug Administration greenlighted the drug, made by Gilead Sciences and sold under the name Truvada, in 2012.
However the CDC also urged use of all other available preventative strategies, including condoms, reduction of risky behavior and use of sterile injection equipment.
A separate analysis also published Tuesday by the CDC suggested that efforts to inform people about the dug could significantly increase its use.
"PrEP only works if patients know about it, have access to it and take it as prescribed," said Jonathan Mermin, director of the CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention.
Researchers at the New York State Department of Health reported that PrEP prescriptions had more than quadrupled among Medicaid users from 303 during July 2013-June 2014 to 1,330 during the same period a year later.
The increase followed a CDC campaign to promote PrEP among doctors and potential users.