PEP: post-exposure prophylaxis (emergency)

PEP (post-exposure prophylaxis) is an emergency treatment that can prevent HIV infection after a possible exposure. Unlike PrEP, which is taken beforehand, PEP is taken after the risk has happened.

When you need PEP

Consider PEP if, in the last 72 hours, you have had a possible exposure to HIV:

• unprotected sex with a person who has HIV or whose status is unknown;
• a condom that broke or slipped;
• sexual assault;
• sharing needles or syringes;
• an accidental needle-stick (for example in a healthcare setting).

The 72-hour rule

PEP must be started as soon as possible — within 72 hours (3 days) of exposure. The earlier you start, the more effective it is. After 72 hours, PEP no longer works.

This is why PEP is a medical emergency: do not wait.

How it works and how it is taken

PEP is a combination of antiretroviral medicines, taken for 28 days. The treatment stops the virus before it can permanently establish itself in the body.

It is important to take every dose, exactly as prescribed, for the full 28 days.

What to do now

1. Go to an emergency department or specialised centre immediately;

2. Explain the situation and ask for PEP;

3. You will have an initial HIV test (PEP is for HIV-negative people) and start treatment if indicated.

After PEP

At the end of treatment and again a few weeks later, you will repeat HIV testing to confirm your status. If you have repeated exposures, your doctor may recommend switching to PrEP for ongoing protection.

See also the Prevention page and the Services list.