PEP (Post-Exposure Prophylaxis) is a month-long course of drugs to help prevent HIV infection that is taken after a possible exposure to HIV.

The sooner someone starts PEP the better, but it must be started within 72 hours after a possible exposure to HIV.

The PEP drugs are the same drugs that HIV-positive people use to reduce its impact on their body.

PEP is short for Post-Exposure Prophylaxis.

Post = after
Exposure = a situation where HIV enters someone’s body (e.g., during sex without a condom or by sharing needles or injecting equipment)
Prophylaxis = prevention of disease

PEP isn’t guaranteed to work but does in the majority of cases.

PEP vs. PrEP

PEP stands for Post-Exposure Prophylaxis and is the focus of this website.
It is a month-long course of drugs to help prevent HIV infection that is taken after a possible exposure to HIV.

PrEP stands for Pre-Exposure Prophylaxis.
It is a drug taken daily over a sustained period to help prevent HIV infection before exposure.
More information about PrEP can be found here.

What are the most common reasons for needing PEP?

  • Sex without a condom with a person who has, or might have, HIV
  • Condom breaking or slipping off during sex
  • Sharing needles or syringes with a person who has, or might have, HIV

How soon should I get PEP?

The sooner PEP is started after exposure to HIV the better, but it needs to be started within 72 hours. The longer you wait, the greater the chance that PEP won’t work. PEP usually isn’t given more than 72 hours (3 days) after exposure as studies show it is unlikely to be effective.

However, if you are unable to access PEP within the 72 hours, even if it has been up to 5-7 days since the exposure occurred, it is still worth seeking medical advice to see what your options are. This may include commencing a 3-drug combination of antiretroviral medications as soon as possible just in case you have become HIV positive. In this case, you would be starting very early treatment and minimising the damage to your immune system.

Is PEP a cure for HIV?

There is no cure for HIV once it has established itself in the body. However, if taken within 72 hours (3 days) of exposure to HIV, PEP can, in most cases, prevent it from establishing itself in the body.

Pros and Cons of taking PEP


  • Taking PEP may prevent you from becoming HIV positive.
  • You only need to take PEP for a month (28 days). If you become HIV positive you may have to take anti-HIV treatments for a lifetime.


  • Some people may experience some side-effects such as nausea and headaches, though some people will experience no side-effects.
  • You have to remember to take PEP at regular times of the day for a month.

Want to talk to someone about PEP?

Some states and territories also have PEP information lines if you want to talk to someone about your risk and if you would be recommended to take PEP, as well as up-to-date locations of where to get PEP. Check out the Get PEP Now section of this website.