Post-exposure prophylaxis (PEP), refers to the drugs that can be taken immediately after someone who is HIV negative is exposed to potentially HIV positive body fluid like blood or semen.PrEP is a prevention method endorsed by the Centers for Disease Control and Prevention (CDC) for people (like you) who are HIV negative but who could be at risk of getting HIV. ART consist of a combination of medications that are recommended as ongoing therapy for those who are HIV positive.