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PROUD results published showing pre-exposure prophylaxis effectively prevents HIV

10 September 2015

Results from the PROUD study, showing a daily pill can effectively protect people from HIV infection, were published today in The Lancet. PROUD is the first study of the pre-exposure prophylaxis approach to preventing HIV to be carried out in the UK. The results show the approach could play a major role in reducing the number of new infections among men who have sex with men.


Pre-exposure prophylaxis (PrEP) is a HIV prevention strategy that involves HIV-negative people taking antiretroviral drugs to reduce the risk of becoming infected if they are exposed to the virus. The PROUD study looked at whether offering daily PrEP to men who have sex with men was an effective way to prevent HIV infection.  The results show that PrEP is highly protective, reducing the risk of infection for this group by 86%.


The drug used in the trial - the antiretroviral Truvada (usually used to treat HIV) - was already known to reduce the incidence of HIV infection in placebo controlled trials.  The PROUD study was designed to see how good Truvada would be found as PrEP 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. 


A total of 544 people from 13 sexual health clinics in England took part in the study. They were men who have sex with men, who reported having had anal sex without a condom in the previous 3 months. The study randomised participants to receive PrEP immediately or to receive PrEP after a period of 12 months, allowing researchers to compare those on PrEP versus those not yet on PrEP. 


Only three men in the immediate PrEP group were infected with HIV, compared to 20 in the group who did not receive PrEP immediately. The three men who were infected in the immediate PrEP group were unlikely to have actually been taking PrEP when they were infected - one was probably infected before he started PrEP, and the other two had not collected their prescription of PrEP for several months before being diagnosed. There was no difference in the number of men diagnosed with other STIs between those on PrEP and those not on PrEP.


For more information about the PROUD study, watch the documentary which contains interviews with researchers, doctors, study participants and community groups.


The number of new HIV infections in the UK has remained stable over the last decade, with approximately 2600 men who have sex with men being newly infected in the UK each year. In order to reduce the number of new infections we need new approaches to preventing the disease, to add to the ones already in use. Adding PrEP to our existing HIV prevention approaches could have a major impact.


The results of PROUD have been welcomed by community organisations including the Terrence Higgins Trust and National AIDS Trust. They are now calling for PrEP to be made available on the NHS. NHS England are currently examining the totality of evidence to support a PrEP programme.
The PROUD study was led by the MRC CTU at UCL and Public Health England in partnership with 12 NHS trusts in England.