PrEP vs PEP at a glance

What is PEP?

PEP (post-exposure prophylaxis), sometimes called the "HIV morning-after pill", is a short course of antiretroviral medicines taken after a possible exposure to HIV. Examples include condomless sex or a condom breaking with a partner who has HIV or whose status is unknown, sharing needles, or a needlestick injury.

PEP is not emergency contraception and does not prevent pregnancy.

How effective is PEP?

The sooner PEP is started, the better it works. Start it as soon as possible, ideally within a few hours, and no later than 72 hours after exposure. Observational studies suggest PEP can reduce the risk of HIV from sexual exposure by more than 80% when it is started promptly and the full 28-day course is taken. It is not 100% effective, so follow-up testing is essential.

Who should consider PEP?

Anyone who may have been exposed to HIV in the last 72 hours, for example:

• After condomless sex, or a broken condom, with a partner who has HIV or whose status is unknown
• After sharing needles or other injecting equipment
• After sexual assault
• After a needlestick or other occupational exposure

How to get and take PEP

1. Go to a clinic or hospital emergency department quickly. Tell the staff you need PEP and when the exposure happened.
2. Get tested before starting. Your doctor will usually test for HIV and check kidney and liver function, and may test for hepatitis B and other STIs.
3. Take PEP every day for 28 days. Do not stop early, even if you feel well.
4. Test again afterwards. Repeat HIV testing is usually done about 4 to 6 weeks and 3 months after the exposure.

Side effects and interactions

Modern PEP medicines are generally well tolerated. Some people have mild nausea, headache or tiredness, which usually improves. Tell your doctor about any other medicines or supplements you take, because PEP can interact with them.

Can I use PEP every time I have unprotected sex?

No. PEP is for emergencies. If you have repeated exposures or have needed PEP more than once, ask your doctor about PrEP instead.

What is PrEP?

PrEP (pre-exposure prophylaxis) is medicine taken by people who do not have HIV to prevent them from getting it. It is usually a daily pill. In some countries, long-acting injectable PrEP given every two months (or twice a year for newer options) is also available.

PrEP must be prescribed by a doctor after a negative HIV test.

Who should consider PrEP?

PrEP may be right for you if you are HIV-negative and any of these apply:

• You have a sexual partner with HIV who does not have an undetectable viral load
• You do not consistently use condoms with new or casual partners
• You have had an STI in the past 6 months
• You inject drugs and share needles or equipment
• You have used PEP more than once

If your partner has HIV and you are planning a pregnancy, ask your doctor whether PrEP can help protect you and your baby.

How effective is PrEP?

Taken as prescribed, PrEP reduces the risk of getting HIV from sex by about 99%, and from injecting drugs by at least 74%. It is much less effective if doses are missed.

Testing and follow-up on PrEP

You will need an HIV test before starting and every 3 months while on PrEP, along with regular checks of kidney function and STI screening. Speak to your doctor if you find daily dosing difficult or want to stop.

Side effects

Some people have mild nausea, headache or stomach upset in the first weeks. These usually settle. Let your doctor know if side effects are bothersome or do not go away.

Where to get PrEP and PEP in Malaysia

PEP is available at hospital emergency departments and many clinics. PrEP is offered at selected government health clinics and at private clinics experienced in HIV prevention. Ask your doctor or local health clinic which options are available near you.

Sources: U.S. Centers for Disease Control and Prevention (CDC), "Post-Exposure Prophylaxis (PEP)" and "Pre-Exposure Prophylaxis (PrEP)" (cdc.gov); World Health Organization, HIV prevention guidance (who.int). This page is for general information and is not medical advice.