Microbicides and PREP are two methods of preventing the spread of HIV that aren’t yet available to the public and are still going through trials to see if they are safe and effective.
It’s hoped that both may become available at some time in the future. The recommendation would probably be that they are used with condoms, not instead of them.
Microbicides
A microbicide is a substance that is usually applied inside a woman’s vagina (possibly a gel, cream or ring that releases a drug). Once in place it acts as a barrier that stops sperm, viruses or bacteria from becoming established in the body during sex.
Work is underway to produce microbicides that kill HIV or otherwise stop the virus infecting a partner during sex. Some aim to deliver anti-HIV drugs into the vagina where they may be able to stop the virus infecting the woman. It may be possible one day to develop microbicides for use in the rectum to stop infection in women and men during anal sex.
Results from recent trials of vaginal microbicides have given mixed results, so if an effective product can be developed it will take a number of years before it is available. Even then, any microbicide would be unlikely to give 100 per cent protection so would need to be used together with another HIV prevention method such as condoms.
PREP
PREP stands for ‘Pre-exposure prophylaxis’. ‘Prohylaxis’ means something that stops an infection happening. ‘Pre-exposure’ means ‘before an event that puts you at risk of infection’ . So, when talking about HIV, ‘Pre-exposure prophylaxis’ means a person, before they have sex with a risk of HIV, uses something to lower their chance of becoming infected.
In trials HIV negative people have been given anti-HIV drugs in the hope this will stop them becoming infected if they have unprotected sex with an HIV positive person. Results in some of these trials have been promising, with PREP significantly lowering the risk of becoming HIV positive and without major side effects.
It is not yet clear how often PREP would need to be taken - ie, all the time or less often that that. But we do know that PREP isn’t as effective as using a condom and people taking PREP have still become infected. If PREP is made available the recommendation may be that it is used with condoms, not instead of them. It will only be available under the supervision of a doctor and may be restricted to people at high risk, such as those in a relationship with an HIV positive partner or people who have many sexual partners but find it very hard to use condoms.
PREP shouldn’t be confused with ‘PEP’ (Post-exposure prophylaxis) which is when someone is given HIV drugs after unprotected sex or a condom failing in an attempt to stop them becoming infected. Our PEP page has further details.