Acquired Immunodeficiency Syndrome (AIDS)

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Acquired immunodeficiency syndrome (AIDS) facts

  • AIDS stands for "acquired immunodeficiency syndrome."
  • AIDS is an advanced stage of infection with the human immunodeficiency virus (HIV). HIV usually is spread from person to person through contact with infected sexual secretions or blood.
  • People with AIDS have weakened immune systems that make them vulnerable to selected conditions and infections.
  • For people infected with HIV, the risk of progression to AIDS increases with the number of years the person has been infected. The risk of progression to AIDS is decreased by using highly effective antiretroviral therapy (ART) regimens.
  • In people with AIDS, art therapy improves the immune system and substantially increases life expectancy. Many patients who are treated with ART have near-normal life expectancies.
  • ART is a treatment that must be continued for life. It is not a cure.
  • It is possible for HIV to become resistant to some antiretroviral medications. The best way to prevent resistance is for the patient to take their ART as directed. If the patient wants to stop a drug because of side effects, he or she should call the physician immediately.
  • If a person is exposed to blood or potentially infectious fluids from a source patient with HIV, the exposed person can take medications to reduce the risk of getting HIV.
  • Research is under way to find a vaccine and cure for HIV.

What does AIDS stand for? What causes AIDS?

AIDS is an acronym for acquired immunodeficiency syndrome." AIDS is caused by the human immunodeficiency virus (HIV) and represents the most advanced stage of HIV infection.

Picture of the HIV/AIDS virus

HIV is spread through contact with infected blood or fluids such as sexual secretions. Over time, the virus attacks the immune system, focusing on special cells called "CD4 cells" which are important in protecting the body from infections and cancers, and the number of these cells starts to fall. Eventually, the CD4 cells fall to a critical level and/or the immune system is weakened so much that it can no longer fight off certain types of infections and cancers. This advanced stage of HIV infection is called AIDS.

HIV is a very small virus that contains ribonucleic acid (RNA) as its genetic material. When HIV infects animal cells, it uses a special enzyme, reverse transcriptase, to turn (transcribe) its RNA into DNA. (Viruses that use reverse transcriptase are sometimes referred to as "retroviruses.") When HIV reproduces, it is prone to making small genetic mistakes or mutations, resulting in viruses that vary slightly from each other. This ability to create minor variations allows HIV to evade the body's immunologic defenses, essentially leading to lifelong infection, and has made it difficult to make an effective vaccine. The mutations also allow HIV to become resistant to antiretroviral medications.

Medically Reviewed by a Doctor on 5/21/2013

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AIDS - Experience Question: What is your personal experience with HIV/AIDS?
AIDS - Signs and Symptoms Question: Please describe your HIV/AIDS signs and symptoms.
AIDS - Risk Factors Question: Did you have any of the HIV risk factors prior to becoming infected?
AIDS - Diagnosis Question: Please describe how your HIV infection was diagnosed.
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Learn about the risks of unprotected sex between HIV-infected partners.

Unprotected Sex Between HIV-Infected Partners: What's the Harm?

At least once a week, I am asked by one of my HIV-infected patients whether they need to continue to practice safe sex if they are in a monogamous (one mate only) relationship with an HIV-infected partner. Put another way, since both partners already have HIV, what's the harm of unprotected sex? Actually, this is not an easy question to answer fully.