In the early 1980s, when the AIDS epidemic began, AIDS patients rarely lived longer than a few years. But today, people infected with HIV, the virus that causes AIDS, have longer and healthier lives. The main reason is that there are many effective medicines to fight the infection. Most medicines fall into one of the following three categories Reverse transcriptase (RT) inhibitors. These medicines interfere with a critical step during the HIV life cycle and keep the virus from reproducing. Protease inhibitors. These medicines interfere with a protein that HIV uses to produce infectious viral particles. Fusion inhibitors. These medicines block the virus from entering the body's cells. While these medicines help people with HIV, they are not perfect. They do not cure HIV infection or AIDS. People with HIV infection still have the virus in their bodies, so even when they are taking medicines they can transmit HIV to others through unprotected sex and needle sharing.