What Is AIDS?

AIDS stands for Acquired immunodeficiency (or immune deficiency) Syndrome. It results from infection with a virus called HIV, which stands for human immunodeficiency virus. This virus infects key cells in the human body called CD4-positive (CD4+) T cells. These cells are part of the body's immune system, which fights infections and various cancers.

When HIV invades the body's CD4+ T cells, the damaged immune system loses its ability to defend against diseases caused by bacteria, viruses, and other microscopic organisms. A substantial decline in CD4+ T cells also leaves the body vulnerable to certain cancers.

There is no cure for AIDS, but medical treatments can slow down the rate at which HIV weakens the immune system. As with other diseases, early detection offers more options for treatment and preventing complications.