Pre-exposure prophylaxis (or PrEP) is medicine taken to prevent getting HIV. PrEP is highly effective for preventing HIV when taken as prescribed.

• PrEP reduces the risk of getting HIV from sex by about 99%.
• PrEP reduces the risk of getting HIV from injection drug use by at least 74%.
• PrEP is less effective when not taken as prescribed. Since PrEP only protects against HIV, condom use is still important for the protection against other STDs. Condom use is also important to help prevent HIV if PrEP is not taken as prescribed.