The Centers for Disease Control and Prevention now believes one in four sexually active gay and bisexual men should take Truvada, an HIV prevention pill.
The conclusion, reached in a new report released Tuesday, suggests potentially millions of people should take the pill daily. The report also found that one in five injection drug users and one in 200 sexually active heterosexual men should also take Truvada.
Currently, only about 21,000 people — fewer than 1 percent who could benefit — take the drug, the CDC's Jonathan Mermin told USA Today.
Truvada, also known as pre-exposure prophylaxis (PrEP), is a daily pill that significantly curtails the risk of getting HIV from an HIV-positive partner. According to the CDC, daily PrEP reduces the risk of getting HIV from sex by more than 90 percent, and the risk of HIV transmission from injecting drugs by more than 70 percent. It's even more effective if used in combination with condoms.
But an alarming number of health care providers don't know of PrEP: A 2015 survey found 34 percent of primary care doctors and nurses have never heard of the drug.
The CDC outlined specific circumstances for which someone would have to take the pill. Generally, it's only deemed necessary if someone engages in risky behavior: sex with an HIV-positive partner, sex with multiple partners, anal sex without a condom, and sharing needles to inject drugs. (If you're curious about whether you should take PrEP, ask your doctor.)
The CDC report comes at a somewhat dire time: Over the past few years, there have been signs that HIV, which about 1.2 million Americans have, is potentially on the rise among some younger populations.
HIV is on the rise among young men who have sex with men
The data is now a bit dated, but in recent years the CDC has found that HIV appears to be on the rise among young men who have sex with men.
A 2014 CDC study found that among all groups, annual HIV diagnoses between 2001 and 2011 increased the most among 13- to 24-year-old boys and men who have sex with men. Previous CDC studies also found a 22 percent increase in new annual HIV infections between 2008 and 2010 among the same group, and youth ages 13 to 24 accounted for more than one in four new HIV infections in the US in 2010.
What's worse, the CDC estimates that more than 50 percent of youth who are HIV-positive don't know they have the virus, making it more likely they'll inadvertently transmit the disease.
In those cases, it would of course be better if people were regularly tested for HIV. If someone is diagnosed, he or she can go on a regimen of antiretroviral medication that can render HIV undetectable, making it much less likely to transmit — several studies of couples in which one person is HIV-positive have found that people with fully suppressed viral loads don't seem to spread the virus even after several years.
But taking PrEP also offers another safeguard. By reducing the risk of transmission by more than 90 percent, it could potentially stop what many public health officials worry may be the return of HIV among younger populations.