What is PrEP for HIV Prevention?
PrEP refers to an experimental HIV prevention strategy that proposes using antiretrovirals (ARVs) to reduce the risk of HIV infection in healthy uninfected people at risk for acquiring the virus. With PrEP, individuals would take a single drug or a combination of drugs orally, or through intramuscular injection, with the hope that it would lower the risk of infection if exposed to HIV. There are for ARVs currently being tested in PrEP human safety and efficacy trials: maraviroc, tenofovir (TDF), rilpivirine (TMC278) and a combination of tenofovir and emtricitabine (FTC). Scientists have focused on these drugs because they can be conveniently taken orally once a day, may have relatively low rates of minor side effects compared to benefit when used as prevention, and because there is significant data on their long-term safety and resistance profiles in HIV positive people. And, in the case of rilpivirine, because it can be taken in long acting formulation by injection.
Global public, philanthropic and commercial sector investment in PrEP increased to US$48 million in 2014, an increase of US$12 million over 2013 (Figure 24). Investment increased by 33 percent in 2014 due in part to a number of new demonstration and implementation projects that began in 2014 focused on the use of PrEP in different settings and populations. Additionally, there are several ongoing studies testing long-acting PrEP formulations, with associated funding of approximately US$13 million.
“PrEP works” was the resounding message from the PrEP research community in 2014. Results from several oral tenofovir-based PrEP studies showed the intervention to be effective at preventing HIV in 2010 and 2011, and research in 2014 moved towards demonstrating its use outside of a clinical trial setting.
- Evidence from two clinical studies—the PROUD study in the UK and the IPERGAY study in France and Canada—showed PrEP to be highly protective against HIV for gay men and other men who have sex with men (MSM) at high risk of infection.
- A secondary analysis of the iPrEX trial provided further support for the efficacy of PrEP use among gay men and other men who have sex with men.
- Additional results also showed that daily PrEP use in serodiscordant couples prevented herpes simplex virus infections.