The Medical Research Council has reported that their Proud study – where people without HIV take a daily dose of medication to prevent getting the virus – is ‘highly protective’ against HIV for gay and other men who have sex with men (MSM).

Speaking at a conference in Seattle, Washington, researchers highlighted that MSM who took part in the trial were at very high risk of HIV, and that PrEP is highly effective in a real world setting. The sexual health research clinics that took part in the Proud study were able to integrate PrEP into their routine HIV risk reduction package with ease. Participants incorporated PrEP into existing risk reduction strategies, which included condom use. There was no difference in the number of men diagnosed with other STIs between those on PrEP and those not on PrEP.

The drug used in the trial – Truvada, which is usually used to treat HIV – was already known to reduce the incidence of HIV infection in placebo controlled trials. The study was designed to see if the same effect would be found in a real world situation where participants knew they were taking an active drug. It aimed to address outstanding questions such as whether taking PrEP would change sexual risk behaviour – for example increasing the number of partners they did not use condoms with and increasing the rate of other sexually transmitted infections (STIs) – and whether or not it would be cost-effective to make it available on the NHS.

It was found that of the 276 people who were given PrEP, just three got HIV, whereas of the 269 people who were studied but not taking the drug, 19 got HIV.

Deborah Gold, chief executive of NAT (National AIDS Trust), said: ‘The study shows two important things – one, that PrEP is highly effective in preventing HIV and two, that gay men won’t just throw away the condoms as soon as they start taking PrEP – STIs were the same in men taking and not taking PrEP.

‘If we can stop people getting HIV by giving them PrEP, we have an ethical duty to do so. Furthermore, over the course of their lifetime the treatment of those 19 men will cost the NHS nearly £7 million. So the financial argument is clear, as is the ethical one. PrEP needs to be available on the NHS as soon as possible for all those who need it.’

Dr Michael Brady, Medical Director at Terrence Higgins Trust, added: ‘PrEP is, quite simply, a game-changer. We know that most gay men use condoms most of the time, and that this has prevented tens of thousands of HIV infections since the epidemic began in the UK. However, we also know that condomless sex vastly increases the risk of HIV being transmitted. This research shows just how effective PrEP can be in preventing transmission of the virus in groups at greatest risk; offering another line of defence alongside condoms and regular testing. It is not a vaccine and it won’t be for everyone, but once approved, we expect it to significantly increase the momentum in our fight against the virus. Therefore, we urge the Government, NHS England and Local Authorities to make PrEP a key priority in the fight against HIV.’