Firstly, it is important to be aware that if someone is HIV positive but is on effective medication and has had an undetectable viral load for more than 6 months it is now recognised that they cannot transmit HIV.
However, if someone is positive but not yet controlled by medication or if they are positive but unaware of their status, the risk of transmission of HIV during penetrative sex can be minimised by always using a condom or femidom. If you are unaware or unsure of a partner’s HIV status you should always use protection. Using a condom or femidom will protect you both against other sexually transmitted infections as well as HIV
There is a very low risk of transmission during oral sex, but you should avoid giving oral sex if you have cuts, sores or ulcers in your mouth. If you are concerned about the risk of transmission during oral sex, you can use a condom or dental dam to reduce the risk.
PEP and PrEP are two new ways that traditional HIV medication can be used to prevent HIV infections. See our section on PEP and PrEP for more information.
If you inject drugs always use sterile injecting equipment and do not share needles. Drug Treatment Services typically offer a needle exchange programme. You can find you local service via NHS Choices.