What is Pre-Exposure Prophylaxis (PrEP)
Pre-exposure prophylaxis, or PrEP, is a drug for people for who do not currently have HIV, but who are at a substantial risk of getting it, to prevent HIV infection. When PrEP is taken daily, this medicine can work to keep the virus from establishing a permanent infection.
When taken consistently over time, studies have shown PrEP to reduce the risk of HIV infection in people who are at risk by up to 92%.
PrEP is a powerful HIV prevention tool and when combined with condoms and other prevention methods, these strategies can provide even greater protection than when using just one alone. For PrEP to be effective, users must commit to taking the drug daily and seeing their health care provider for a follow-up every 3 months.
Can anyone use PrEP?
PrEP is not for everyone. Federal guidelines recommend that PrEP be considered for people who are HIV-negative and at very high risk for HIV infection. This included anyone who is in an ongoing relationship with an HIV-positive partner. It also includes anyone who:
- Is not in a mutually monogamous relationship with a partner who recently tested HIV-negative.
- Is a gay or bisexual man who has had anal sex without a condom or been diagnosed with a sexually transmitted infection within the past 6 months.
- Is a male that has had sex with both men and women.
- Is a heterosexual man or women who does not regularly use condoms during sex with partners of unknown HIV status who are at a substantial risk of HIV infection (e.g., people who inject drugs or women who have bisexual male partners.)
PrEP is also recommended for people who have injected drugs, and, or shared needles in the past 6 months.
If you have a partner who is HIV-positive and are considering getting pregnant, talk to your doctor about PrEP. It may be an option to protect you and your baby.
PrEP is only for people who are at a substantial ongoing risk of HIV infection. For people who need to prevent HIV after a single high-risk event of potential HIV exposure—such as sex without a condom, needle-sharing injection drug use, or sexual assault—there is another option called post-exposure prophylaxis, or PEP. PEP must begin within 72 hours of exposure. See our PEP page for more information.
Important reminder, taking PrEP will not prevent you from getting syphilis, gonorrhea, chlamydia, or other sexually transmitted diseases. Similarly, for those taking PrEP because of injection drug use risks, PrEP will not protect you from getting hepatitis C, skin, or heart infections.
How well does PrEP work?
When taken every day, PrEP has been shown to reduce the risk of HIV infection in people who are at high risk by more than 90%. PrEP is much less effective if it is not taken consistently. PrEP can be even more effective if it is combined with other ways to prevent new HIV infections like condom use, drug abuse treatment, and treatment for people living with HIV.
Is PrEP safe?
Some people in clinical studies of PrEP had early side effects such as an upset stomach or loss of appetite, but these were mild and usually went away within the first month. Some people also had mild headache. No serious side effects were observed. If you are on PrEP, you should tell your healthcare provider if these or other symptoms become severe or do not go away.
Why take PrEP?
The HIV epidemic in the United States is growing. About 50,000 people get infected with HIV each year. There are specific demographic and geographic areas experiencing more HIV growth than others. If you are in one of these high-risk groups then PrEP could help drastically reduce your chances of infection.
Guidelines for PrEP use.
In May 2014, the U.S. Public Health Service and the CDC issued clinical practice guidelines for the use of PrEP in the U.S., along with a clinical providers’ supplement. These resources advise healthcare providers on determining when PrEP is right for various patients.
Where can I get PrEP?
If you think you may be at high risk for HIV, talk to your healthcare provider about whether PrEP is right for you.
Please see CDC’s brochure Talk to Your Doctor About PrEP for questions that you should ask your healthcare provider when discussing if PrEP is right for you.
What medications are used in PrEP?
The pill approved by the U.S. Food and Drug Administration (FDA) for daily use as PrEP for people at very high risk of getting HIV infection is called Truvada®. Truvada® is a combination of two HIV medications (tenofovir and emtricitabine). These medicines work by blocking important pathways that HIV uses to set up an infection. If you take PrEP daily, the presence of the medicine in your bloodstream can often stop HIV from taking hold and spreading in your body. If you do not take PrEP every day, there may not be enough medicine in your bloodstream to block the virus. PrEP can only be prescribed by a health care provider and must be taken as directed to be effective.