HIV stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome, or AIDS, if not treated. Unlike some other viruses, the human body can’t get rid of HIV completely, even with treatment. So once you get HIV, you have it for life.
HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. Untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get other infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection.
AIDS is the most severe phase of HIV infection. AIDS stands for Acquired Immune Deficiency Syndrome.
This is the stage of HIV infection that occurs when your immune system is badly damaged and you become vulnerable to opportunistic infections. When the number of your CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3), you are considered to have progressed to AIDS. (In someone with a healthy immune system, CD4 counts are between 500 and 1,600 cells/mm3.) You are also considered to have progressed to AIDS if you develop one or more opportunistic illnesses, regardless of your CD4 count.
No effective cure currently exists for HIV. But with proper medical care, HIV can be controlled. Treatment for HIV is called antiretroviral therapy or ART. If taken the right way, every day, ART can dramatically prolong the lives of many people infected with HIV, keep them healthy, and greatly lower their chance of infecting others. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS (the last stage of HIV infection) in a few years. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.
Learn about how to protect yourself, and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
You can get or transmit HIV only through specific activities. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use.
Only certain body fluids—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from a person who has HIV can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth.
In the United States, HIV is spread mainly by
Less commonly, HIV may be spread
No. HIV is NOT transmitted:
As noted above, only certain body fluids—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from an HIV-infected person can transmit HIV. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use. Babies can also get HIV from an HIV-positive mother during pregnancy, birth, or breastfeeding.
If you’re HIV-negative:
If you’re HIV-positive:
If you’re a health care professional:
Learn about how to protect yourself, and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool (BETA).
The only way to know for sure whether you have HIV is to get tested. CDC recommends that everyone between the ages of 13 and 64 get tested for HIV at least once as part of routine health care. Knowing your HIV status gives you powerful information to help you take steps to keep you and your partner(s) healthy. About 1 in 7 people in the United States who have HIV do not know they have it.
You can ask your health care provider for an HIV test. Many medical clinics, substance abuse programs, community health centers, and hospitals offer them too. You can also find a testing site near you by: