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PEP (post-exposure prophylaxis) means taking antiretroviral medicines (ART) after being potentially exposed to HIV to prevent becoming infected.
PEP should be used only in emergency situations and must be started within 72 hours after a recent possible exposure to HIV. If you think you’ve recently been exposed to HIV during sex or through sharing needles and works to prepare drugs or if you’ve been sexually assaulted, talk to your health care provider or an emergency room doctor about PEP right away.
For more information on PEP, visit Preventing New HIV Infections. For providers, see updated nPEP guidelines.
What is PEP?
PEP stands for post-exposure prophylaxis. It means taking antiretroviral medicines (ART) after being potentially exposed to HIV to prevent becoming infected.
PEP must be started within 72 hours after a recent possible exposure to HIV, but the sooner you start PEP, the better. Every hour counts. If you’re prescribed PEP, you’ll need to take it once or twice daily for 28 days. PEP is effective in preventing HIV when administered correctly, but not 100%.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
Is PEP right for me?
If you’re HIV-negative or don’t know your HIV status, and in the last 72 hours you
- think you may have been exposed to HIV during sex (for example, if the condom broke),
- shared needles and works to prepare drugs (for example, cotton, cookers, water), or
- were sexually assaulted,
talk to your health care provider or an emergency room doctor about PEP right away.
PEP should be used only in emergency situations and must be started within 72 hours after a recent possible exposure to HIV. It is not a substitute for regular use of other proven HIV prevention methods, such as pre-exposure prophylaxis (PrEP), which means taking HIV medicines daily to lower your chance of getting infected; using condoms the right way every time you have sex; and using only your own new, sterile needles and works every time you inject.
PEP is effective, but not 100%, so you should continue to use condoms with sex partners and safe injection practices while taking PEP. These strategies can protect you from being exposed to HIV again and reduce the chances of transmitting HIV to others if you do become infected while you’re on PEP.
If you’re a health care worker and think you’ve had a possible HIV exposure at work, see the following question.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
I’m a health care worker, and I think I’ve been exposed to HIV at work. Should I take PEP?
PEP should be considered if you’ve had a recent possible exposure to HIV at work. Report your exposure to your supervisor, and seek medical attention immediately.
Occupational transmission of HIV to health care workers is extremely rare, and the proper use of safety devices and barriers can help minimize the risk of exposure while caring for patients with HIV.
A health care worker who has a possible exposure should see a doctor or visit an emergency room immediately. PEP must be started within 72 hours after a recent possible exposure to HIV. The sooner, the better; every hour counts.
CDC issued updated guidelines in 2013 for the management of health care worker exposures to HIV and recommendations for PEP.
Clinicians caring for health care workers who’ve had a possible exposure can call the PEPline (1-888-448-4911), which offers around-the-clock advice on managing occupational exposures to HIV, as well as hepatitis B and C. Exposed health care workers may also call the PEPline, but they should seek local medical attention first.
Read more about occupational exposure to HIV and strategies to prevent it in this CDC fact sheet.
When should I take PEP?
PEP must be started within 72 hours after a possible exposure. The sooner you start PEP, the better; every hour counts.
Starting PEP as soon as possible after a potential HIV exposure is important. Research has shown that PEP has little or no effect in preventing HIV infection if it is started later than 72 hours after HIV exposure.
If you’re prescribed PEP, you’ll need to take it once or twice daily for 28 days.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
Does PEP have any side effects?
PEP is safe but may cause side effects like nausea in some people. These side effects can be treated and aren’t life-threatening.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
Where can I get PEP?
Your health care provider or an emergency room doctor can prescribe PEP. Talk to them right away if you think you’ve recently been exposed to HIV.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
How can I pay for PEP?
If you’re prescribed PEP after a sexual assault, you may qualify for partial or total reimbursement for medicines and clinical care costs through the Office for Victims of Crime, funded by the US Department of Justice (see the contact information for each state).
If you’re prescribed PEP for another reason and you cannot get insurance coverage (Medicaid, Medicare, private, or employer-based), your health care provider can apply for free PEP medicines through the medication assistance programs run by the manufacturers. Online applications can be faxed to the company, or some companies have special phone lines. These can be handled urgently in many cases to avoid a delay in getting medicine.
If you’re a health care worker who was exposed to HIV on the job, your workplace health insurance or workers’ compensation will usually pay for PEP.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
Can I take a round of PEP every time I have unprotected sex?
PEP should be used only in emergency situations.
PEP is not the right choice for people who may be exposed to HIV frequently—for example, if you often have sex without a condom with a partner who is HIV-positive. Because PEP is given after a potential exposure to HIV, more drugs and higher doses are needed to block infection than with PrEP, or pre-exposure prophylaxis. PrEP is when people at high risk for HIV take HIV medicines (sold under the brand name Truvada) daily to lower their chances of getting HIV. If you are at ongoing risk for HIV, speak to your doctor about PrEP. Also, read our Q&As on PrEP.
Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
Content provided and maintained by the US Centers for Disease Control and Prevention (CDC). Please see our system usage guidelines and disclaimer.
- Page last reviewed: June 6, 2017
- Page last updated: June 6, 2017
- Content source: Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention