AIDS (acquired immunodeficiency syndrome) is caused by HIV (human immunodeficiency virus). HIV is most commonly spread through IV drug use and by sexual intercourse with an infected partner. It can also be spread through contact with infected blood, and women can transmit the virus to their babies during pregnancy or birth. By killing or damaging cells in
the body’s immune system, HIV progressively destroys the body’s ability to fight infections. The term AIDS applies to the most advanced stages of HIV infection.