for Veterans and the Public
Frequently Asked Questions
Q: Can you reduce the risk of getting HIV after having unprotected sex with someone who has HIV?
Let's say you had sex with someone who has HIV infection and the condom broke, or you found out only after condomless sex that your partner had HIV. Can you reduce your risk of getting HIV from sex--or from a needlestick--by taking medications afterward?
Yes. This is called postexposure prophylaxis, or PEP.
The medications that are given for PEP are the same types that are used to treat HIV (antiretrovirals, or ARVs), and they usually are given as a combination of 3 medicines for 1 month. To work best, these ARVs should be taken as soon as possible after the exposure, and ideally not later than 72 hours (3 days) after the exposure. To be evaluated for PEP, the exposed individual should contact his/her clinician or an emergency room promptly after the exposure. If the provider is unsure about whether or how to give PEP, he/she can call the free 24-hour National Clinicians' Consultation Center (NCCC) PEPline at 888-448-4911. Many emergency rooms and insurance plans will provide the ARVs for PEP.
Exposed persons do not have to know the HIV status of the person with whom they had contact in order to be offered PEP--providers will evaluate the risk level of the exposure and, if possible, offer testing to the source individual. The exposed person should be tested to see if they already (without knowing it) have HIV or other sexually transmitted diseases such as hepatitis B, gonorrhea, chlamydia, and syphilis, but the first dose of PEP should not be delayed in order to complete that testing. The sooner after the exposure PEP medicines are started, the more likely they are to be effective. People on PEP should be monitored for side effects from the PEP medicines and tested again for HIV after the treatment is completed.
If you have a partner who is HIV-positive, or if you have had to take PEP more than once, you might want to consider taking pre-exposure prophylaxis (PrEP). PrEP is an ARV pill that people who are at risk of getting HIV can take every day to prevent HIV infection. See our other FAQs on PrEP or speak with your provider.