Pre-exposure prophylaxis (or PrEP) is when people at very high risk for HIV take HIV medicines daily to lower their chances of getting infected. PrEP can stop HIV from taking hold and spreading throughout your body. It is highly effective for preventing HIV if used as prescribed, but it is much less effective when not taken consistently.
Daily PrEP reduces the risk of getting HIV from sex by more than 90%. Among people who inject drugs, it reduces the risk by more than 70%. Your risk of getting HIV from sex can be even lower if you combine PrEP with condoms and other prevention methods.
What is PrEP?
Pre-exposure prophylaxis (or PrEP) is when people at very high risk for HIV take HIV medicines daily to lower their chances of getting infected. A combination of two HIV medicines (tenofovir and emtricitabine), sold under the name Truvada® (pronounced tru vá duh), is approved for daily use as PrEP to help prevent an HIV-negative person from getting HIV from a sexual or injection-drug-using partner who’s positive. Studies have shown that PrEP is highly effective for preventing HIV if it is used as prescribed. PrEP is much less effective when it is not taken consistently.
Why Take PrEP?
For those at very high risk for HIV, PrEP can significantly reduce your risk of HIV infection if taken daily. Daily PrEP use can lower the risk of getting HIV from sex by more than 90% and from injection drug use by more than 70%. You can combine additional strategies with PrEP to reduce your risk even further.
Should I Consider Taking PrEP?
PrEP is for people without HIV who are at very high risk for getting it from sex or injection drug use. The federal guidelines recommend that PrEP be considered for people who are HIV-negative and in an ongoing sexual relationship with an HIV-positive partner.
This recommendation also includes anyone who
- isn’t in a mutually monogamous* relationship with a partner who recently tested HIV-negative, and
- is a . . .
- gay or bisexual man who has had anal sex without using a condom or been diagnosed with an STD in the past 6 months, or
- heterosexual man or woman who does not regularly use condoms during sex with partners of unknown HIV status who are at substantial risk of HIV infection (for example, people who inject drugs or women who have bisexual male partners).
PrEP is also recommended for people who have injected drugs in the past 6 months and have shared needles or works or been in drug treatment 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 if you’re not already taking it. PrEP may be an option to help protect you and your baby from getting HIV infection while you try to get pregnant, during pregnancy, or while breastfeeding.
Because PrEP involves daily medication and regular visits to a health care provider, it may not be right for everyone. And PrEP may cause side effects like nausea in some people, but these generally subside over time. These side effects aren’t life threatening. See Is PrEP safe?, below.
* Mutually monogamous means that you and your partner only have sex with each other and do not have sex outside the relationship.
How Well Does PrEP Work?
Studies have shown that PrEP reduces the risk of getting HIV from sex by more than 90% when used consistently. Among people who inject drugs, PrEP reduces the risk of getting HIV by more than 70% when used consistently.
Visit CDC’s website for links to these studies.
Is PrEP Safe?
PrEP can cause side effects like nausea in some people, but these generally subside over time. No serious side effects have been observed, and these side effects aren’t life threatening. If you are taking PrEP, tell your health care provider about any side effects that are severe or do not go away.
How Can I Start PrEP?
PrEP can be prescribed only by a health care provider, so talk to yours to find out if PrEP is the right HIV prevention strategy for you. You must take PrEP daily for it to work. Also, you must take an HIV test before beginning PrEP to be sure you don’t already have HIV and every 3 months while you’re taking it, so you’ll have to visit your health care provider for regular follow-ups.
The cost of PrEP is covered by many health insurance plans, and a commercial medication assistance program provides free PrEP to people with limited income and no insurance to cover PrEP care.
Learn More About PrEP
If you think PrEP might be right for you, visit CDC’s PrEP Basics.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).