The Proud study, conducted in England, provides the first evidence that prophylactic HIV treatment is highly effective in a real-world setting.
It showed that pre-exposure to the HIV drug Truvada can reduce the risk of infection in men who have sex with men (MSM) by as much as 86 per cent.
Previous research had suggested that prophylactic treatment might cut HIV infection rates but it was unclear whether such an approach would work in practice.
The new study recruited 545 participants at 13 sexual health clinics in England. They were divided into two groups, one of which was to be given Truvada immediately and the other a year later.
Comparing the two made it possible to assess the effectiveness of pre-exposure prophylaxis (PrEP) in men at high risk of HIV infection. Of the 276 men treated immediately, three were infected with HIV over the subsequent year.
During the same period, 19 of the men from the “deferred group” became HIV positive.
Chief investigator Professor Sheena McCormack, from the Medical Research Council’s clinical trials unit at University College London, said: “These results are extremely exciting and show PrEP is highly effective at preventing HIV infection in the real world.
“Concerns that PrEP would not work so well in the real world were unfounded.
“These results show there is a need for PrEP, and offer hope of reversing the epidemic among men who have sex with men in this country. The findings we’ve presented today are going to be invaluable in informing discussions about making PrEP available through the NHS.”
Dr Michael Brady, medical director at the HIV/Aids charity Terrence Higgins Trust, said: “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 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.”
The findings, presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, US, also showed that taking a drug to protect against HIV did not appear to alter rates of condom use.
SCOTSMAN TABLET AND MOBILE APPS