Pre-exposure prophylaxis, or PrEP, is a new HIV prevention method in which people who do not have HIV infection take a pill daily to reduce their risk of becoming infected. The pill, called Truvada®, contains two of the many medications that can be used to treat people who already have HIV. These medications prevent HIV from making copies of itself and turning into an infection that’s spread throughout your body.  In this way PrEP medicines can help keep the virus from establishing a permanent infection. So, PrEP is a way for people who are at very high risk of getting HIV to lower their risk by taking a daily pill.  PrEP is only meant for people at very high risk for getting HIV because they may often be exposed to the virus—for example, someone who is HIV-negative but has an HIV-positive partner and doesn’t consistently use condoms. 

Continue reading at http://www.aids.gov/hiv-aids-basics/prevention/reduce-your-risk/pre-exposure-prophylaxis/