Pre-exposure prophylaxis (PrEP)
The guidance is based on clinical trials indicating that a daily dose of oral antiretroviral medication, known as pre-exposure prophylaxis (PrEP), taken by HIV-negative people to reduce the risk of infection, is both safe for people to use and effective in preventing HIV. The iPrEX study shows that use of PrEP can reduce HIV infection by around 40% among men who have sex with men – and up to 73% among those who took the medicine regularly. The Partners PrEP study found 75% protection among serodiscordant couples (couples in which one person is HIV positive) in Kenya and Uganda.
The range of results in these studies highlight the potential benefits of PrEP, but also the importance of combining it with consistent use of condoms, as well as frequent HIV testing, counselling, and treatment of sexually transmitted infections.
They also emphasize the importance of taking medicines every day. Many people who are at high risk for HIV may not easily be able to incorporate the diligent treatment regimen required, so the next challenge is to ascertain how best to deliver PrEP to those who would benefit from it in ‘real life’ settings in order to achieve the necessary adherence and maximum public health gains.
PrEP projects in countries
To better understand how PrEP can best contribute to a combination HIV prevention programme, WHO is encouraging countries wishing to introduce PrEP to first establish small projects to help public health workers to better understand and realize its potential benefits. In these projects, ARVs would be given to people at high risk of HIV infection. These could include uninfected men or transgender women who have sex with men who have a high risk of being HIV-positive. The aim is to identify which groups will benefit most from PrEP, and ascertain the best ways to deliver the services to them.
WHO will evaluate the outcome of these projects, together with the evolving scientific evidence. The results will help determine the best way to integrate PrEP guidance in future consolidated WHO guidelines on the use of antiretrovirals for preventing and treating HIV infection, which are expected in the summer of 2013.
Today’s new guidance recommends that the projects pay particular attention to:
- ensuring that people seeking PrEP are, in fact, HIV-negative, to guard against the development of drug resistance;
- encouraging people using PrEP to continue using condoms;
- checking that people seeking PrEP do not have medical conditions which would make taking ARVs inappropriate (e.g. pre-existing kidney or bone disease);
- monitoring for any adverse events;
- helping people using PrEP to adhere to the drug regimen of taking daily medication;
- ensuring that people using PrEP have easy access to an uninterrupted supply of their medicine at a convenient time and place;
- regularly testing for HIV infection in people who are taking PrEP, and checking for any sign of drug resistance if infection is found;
- ensuring continued access to HIV prevention services for those who stop taking PrEP;
- gathering more information on the cost-benefits of PrEP to help countries make decisions about how best to allocate limited resources, especially where not all people who need HIV treatment have access to it.
The United States Food and Drug Administration this week approved the use of ARVs as part of a comprehensive HIV prevention strategy for the country that includes condom use and other safe practices as well as testing and counselling. The manufacturer of the approved pill estimates that the medicine will typically cost US$13 900 per person per year in the United States.
Notes to editors
The XIX International AIDS Conference is taking place in Washington DC, 22–27 July 2012. The theme of the conference is “Turning the Tide Together”. WHO is presenting proposals to accelerate the elimination of HIV transmission, linking the latest science with what can be done on the ground. This includes a discussion paper on strategic use of antiretrovirals; a global report on drug resistance; guidance on the prevention and treatment of HIV and sexually transmitted infections among sex workers; and guidance on the prevention of hepatitis (a common co-infection with HIV) among people who inject drugs.
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