What is HIV Post-Exposure Prophylaxis (PEP)?
Post-exposure prophylaxis (PEP) for HIV means taking medicine called antiretroviral drugs after being exposed to HIV. These drugs help lower the chance of getting HIV by fighting the virus before it can cause an infection in the body. Research shows that PEP can reduce the risk of getting HIV by 80% or more when taken correctly.
When should I take PEP?
PEP should be started as soon as possible, ideally within 24 hours, and no later than 72 hours (3 days) after a potential exposure. PEP started after the 72-hour period may not prevent HIV infection. The sooner PEP is started, the more effective it is. It is for emergency situations and is not a substitute for pre-exposure HIV prevention, such as condoms or Pre-Exposure Prophylaxis (PrEP) for those who are frequently at risk.
How does PEP work?
PEP involves a 28-day course of two or three medications, taken daily. PEP medications are antiretroviral drugs that prevent HIV from making more copies of itself. Each medication stops HIV at a different point in its infection process. Combining medications that work in different ways makes the treatment more effective.
It is important to note that starting PEP after an HIV exposure may mean multiple visits with a healthcare provider for close monitoring and testing over the course of the treatment and for several weeks after. PEP is usually safe, and most people do not have serious problems when taking it. The most common side effects include nausea, vomiting, diarrhea, and fatigue. These are usually mild and can be treated.
For individuals at ongoing risk of being exposed to HIV, starting pre-exposure prophylaxis (PrEP) after completing the 28-day PEP regimen can prevent HIV infection for other potential exposures in the future.
What is an exposure?
PEP is only recommended for a potential exposure to HIV that has occurred within the past 72 hours. Exposures include:
- Unprotected vaginal or anal sex with a partner with known HIV or a partner with unknown HIV status
- Shared needles or other equipment (works) to inject drugs
- After a sexual assault
- Contact with blood through non-intact skin (open cut or wound) or mucus membrane (eyes, nose, mouth, etc.)
If I have had an exposure, what should I do?
Being exposed to HIV is a medical emergency. If you think you have been exposed to HIV within the last 72 hours (3 days), you should get medical help. Go to a hospital emergency room (ER) as soon as possible. A doctor or nurse will review your exposure risk and decide if PEP is the right treatment for you. Most ERs can give you PEP right away.
PEP and workplace exposures
If you think you've been exposed to HIV at work, see a health care provider, an emergency room doctor, or an urgent care provider right away. Report your exposure to the appropriate person at work and seek medical attention immediately. Healthcare workers should contact their Occupational Health department as soon as possible, if available. Careful practice of standard precautions can help reduce workplace exposure while caring for patients with HIV.
Clinicians caring for workers who've had a possible exposure can call the PEPline (1-888-448-4911) for advice on managing occupational exposures to HIV. Exposed workers may also call the PEPline, but they should seek medical attention first.
PEP resources
- Any prescribing clinician can provide PEP.
- For evaluation, you can go to:
- Your primary care provider
- A community health center
- An urgent care center
- A hospital emergency room
- PEP is covered by most health insurance plans.
- For eligible individuals who are uninsured/underinsured or face challenges to pay for PEP, the Massachusetts Infectious Disease Drug Assistance Program (IDDAP) can pay for PEP medications.
- Learn more about the Massachusetts Non-Occupational Post-Exposure Prophylaxis (nPEP) Program through Community Resource Initiative.
For healthcare providers
If you are a medical professional who is unsure if you should administer PEP, you should call the National Clinicians' Post-Exposure Prophylaxis Hotline (PEPline) at (888) 448-4911 for consultation. They are available between 9 a.m. and 2 a.m. ET. Hotline staff will help determine if PEP should be administered and recommend a treatment regimen tailored to the specific exposure and characteristics of the exposed individual.
Additional considerations for sexual assault survivors
In addition to an assessment for PEP, sexual assault survivors should also be referred to the Sexual Assault Nurse Examiner (SANE) Program whenever possible to be evaluated for other sexually transmitted infections in addition to HIV.
SANEs are specially trained and certified professionals skilled in performing quality forensic medical-legal exams. SANEs are available at all times and respond immediately to the designated SANE site ready to care for the victim of a sexual assault age 12 and over.