What is HIV?

"HIV" stands for Human Immunodeficiency Virus.

• H - This particular virus can only infect human beings.
• I - Immunodeficiency - HIV weakens your immune system by destroying important cells that fight disease and infection. A "deficient" immune system can't fully protect you.
• V - A virus can only reproduce itself by using a cell in the body of its host.

At the end of 2012, about 1.2 million people in the United States were living with HIV. Some groups of people in the United States are more likely to get HIV than others because of many factors, including the status of their sex partners, their risk behaviors, and where they live.

When people get HIV and don't take medicine to treat HIV, they will typically progress through three stages of disease one after the other: 1) acute HIV infection; 2) clinical latency, and 3) acquired immunodeficiency syndrome (AIDS).

There are also different types of HIV. It is possible, though rare, for people living with HIV to get infected with more than one type of HIV; this is called superinfection.