PEP stands for Post-Exposure Prophylaxis. PrEP stands for Pre-Exposure Prophylaxis. Both involve using antiretroviral drugs to prevent HIV infection.
PEP has long been used in hospitals and other "occupational" settings. It involves giving a short course of antiretroviral treatment to someone who may have been exposed to HIV, such as a hospital worker who is accidentally stuck with a sharp instrument or needle that was recently used on someone known to be infected with the virus. In this situation, a 28-day course of HIV treatment—usually a combination of two or three approved antiretrovirals—is started to help prevent the virus from establishing infection in the body.
PEP can also be used in "non-occupational" situations, such as possible exposure to the virus after sexual activity or injection drug use. According to guidelines from the CDC, however, It is only intended for people who have engaged in high-risk activity with someone known to be HIV positive and when the person seeks care within 72 hours of exposure. As with possible occupational exposure to the virus, it is best if PEP is started within hours of a possible non-occupational exposure. It will not likely be effective if started more than 48 to 72 hours after possible exposure.
If you fear that you may have been exposed to HIV and are trying to figure out if PEP is right for you, get in touch with your doctor or a nearby hospital emergency room immediately!
PrEP is an experimental HIV prevention approach. It involves using HIV medications before possible exposure to the virus. The concept of providing a preventive before exposure to an infectious agent is not new. For example, travelers to an area where malaria is common are advised to take medication before and during travel to prevent the disease. The medicine to prevent illness is then already in their bloodstream if they are exposed to the malaria parasite. Researchers believe that the same concept may work to protect people from HIV infection. Theoretically, if HIV replication can be inhibited from the moment the virus enters the body, it may not be able to establish a permanent infection.
PrEP studies are still being conducted to determine if this approach is safe and effective. Because more information from these studies is necessary, groups like the CDC do not yet have recommendations regarding PrEP. To learn more about this possible HIV prevention strategy, click here.
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