Learn more about the terminology used in the Ending the HIV Epidemic: A Plan for America initiative.

Two people looking at each other, smiling

Click on a term to view its definition.


Pre-exposure prophylaxis (or PrEP) is daily medicine that people at very high risk for HIV can take to prevent HIV. PrEP medications can stop HIV from taking hold and spreading throughout your body. When taken daily, PrEP medication is highly effective for preventing HIV from sex or injection drug use. PrEP is much less effective when it is not taken consistently.

Formula for the PrEP Coverage indicator