PrEP, short for pre-exposure prophylaxis, is a medicine that can reduce a person's chances of getting infected with HIV.

It works by stopping HIV from taking hold and spreading throughout the body.

PrEP is taken before a person's exposure to HIV and is meant to be an additional tool to reduce the risk of infection from the disease.

It is meant to supplement, not replace, condoms, which are an effective preventive method against HIV.

The pill is taken once a day. It contains two medicines - tenofovir and emtricitabine - that are also used to treat HIV.

What do the studies show?

PrEP has been shown to reduce the risk of HIV infection through sex for gay and bisexual men, transgender women, heterosexual men and women, as well as people who inject drugs.

It can cut the risk by more than 90 per cent.

PrEP does not work after you stop taking it.

Who is it for?

It is for HIV-negative people or those who do not have HIV infection, but who have a very high risk of getting it.

These include sexually active gay men and anyone who is in a relationship with a HIV-positive partner.

Are there any side effects?

Side effects are uncommon.

Studies show that some people get early side effects such as an upset stomach or loss of appetite, but these were mild and usually went away within the first month.

Some people reported having mild headaches. But no serious side effects were observed.

•Sources: Action for Aids Singapore, US-based prepfacts.org and Aids.gov

Where to get PrEP?

Be Prepared Clinic

NUH Medical Centre Call 6772-8686 or send an e-mail to umcapptline@nuhs.edu.sg

TTSH

Call 6357-7000

DSC Clinic

31 Kelantan Lane Call 6293-9648 or send an e-mail to apptdsc@nsc.com.sg