Pre-exposure prophylaxis (PrEP) is a course of HIV drugs taken by an HIV negative person to lower the chance of becoming infected with HIV in the future. There are different ways you can take PrEP. You can take it every day for continuous protection. Alternatively, if you can predict your risk in advance you can use the ‘event based’ option.

The advice is based on two studies (Ipergay and PROUD) which looked at different ways of taking the treatment. Both studies showed an 86% reduction in catching HIV. In PROUD study (done in the UK) people took PrEP every day. In the Ipergay study the person took PrEP around an “event” – they took two PrEP pills between 2-24 hours before sex, then one PrEP pill every day until two days had passed after the last unprotected sex. The Ipergay regimen is not recommended for vaginal sex. No one in either study who took PrEP as directed became HIV positive.

Before and every three months whilst you are taking PrEP you need to attend a sexual health clinic for baseline and regular HIV tests, checks on your kidney, your hepatitis status check and full sexual health screening.

You can get PrEP via

  • The PrEP Impact study – this offers NHS funded PrEP to people at high risk of catching HIV.
  • You can buy PrEP online for your own use.

Some scenarios where you might consider starting on PrEP include

  • You are a gay or bisexual man and have recently had unprotected anal sex and are likely to have it again in the next few months
  • You have an HIV positive partner who is not on treatment and you are likely to have unprotected sex with that person.
  • You have recently had a rectal STI (gonorrhoea, LGV or chlamydia in your anus) or syphilis.
  • You have used PEP (post exposure prophylaxis) in the last few months
  • You participate in chemsex parties

PrEP is not recommended if you are already HIV positive. Nor is it recommended if you have an HIV positive partner who has been taking treatment for a while and has an undetectable viral load. In this situation the risk of catching HIV (if they are your only partner) is near to zero.