How does PrEP differ from PEP?
PEP, or post-exposure prophylaxis, is an HIV prevention strategy that uses a course of antiretroviral drugs which is thought to reduce the risk of HIV after events with high risk of exposure to HIV (e.g., unprotected anal or vaginal sex, needle stick pricks, or the sharing of needles.) Ideally PEP should begin within an hour of possible infection and no longer than 72 hours after exposure, whereas PrEP would be taken over time — either daily or intermittently — before high-risk exposure may take place.