Sunday, March 7, 2010


AIDS stands for Acquired Immune Deficiency Syndrome: Acquired means you can get infected with it;

  • Immune Deficiency means a weakness in the body's system that fights diseases.
  • Syndrome means a group of health problems that make up a disease.

AIDS is caused by a virus called HIV, the Human Immunodeficiency Virus. If you get infected with HIV, your body will try to fight the infection. It will make "antibodies," special molecules to fight HIV.

A blood test for HIV looks for these antibodies. If you have them in your blood, it means that you have HIV infection. People who have the HIV antibodies are called "HIV-Positive." Fact Sheet 102 has more information on HIV testing.

Being HIV-positive, or having HIV disease, is not the same as having AIDS. Many people are HIV-positive but don't get sick for many years. As HIV disease continues, it slowly wears down the immune system. Viruses, parasites, fungi and bacteria that usually don't cause any problems can make you very sick if your immune system is damaged. These are called "opportunistic infections." See Fact Sheet 500 for an overview of opportunistic infections.

You don't actually "get" AIDS. You might get infected with HIV, and later you might develop AIDS. You can get infected with HIV from anyone who's infected, even if they don't look sick and even if they haven't tested HIV-positive yet. The blood, vaginal fluid, semen, and breast milk of people infected with HIV has enough of the virus in it to infect other people. Most people get the HIV virus by:

  • having sex with an infected person
  • sharing a needle (shooting drugs) with someone who's infected
  • being born when their mother is infected, or drinking the breast milk of an infected woman

Getting a transfusion of infected blood used to be a way people got AIDS, but now the blood supply is screened very carefully and the risk is extremely low.

There are no documented cases of HIV being transmitted by tears or saliva, but it is possible to be infected with HIV through oral sex or in rare cases through deep kissing, especially if you have open sores in your mouth or bleeding gums.

The Centers for Disease Control and Prevention (CDC) estimates that 1 to 1.2 million U.S. residents are living with HIV infection or AIDS; about a quarter of them do not know they have it. About 75 percent of the 40,000 new infections each year are in men, and about 25 percent in women. About half of the new infections are in Blacks, even though they make up only 12 percent of the US population.

In the mid-1990s, AIDS was a leading cause of death. However, newer treatments have cut the AIDS death rate significantly. For more information, see the US Government fact sheet at