What is the difference between HIV and AIDS?

Question: What is the difference between HIV and AIDS?

Answer: The quick answer is that the difference between HIV and AIDS is that HIV is a virus and AIDS is a definition.

What does HIV stand for?

HIV stands for "human immunodeficiency virus." In other words, it is a virus that infects human being and leads to problems with their immune system. The immune system is the body's system for fighting disease.

It is made up of several types of cells that, working together with specialized proteins such as antibodies, fight bacteria, viruses, and other agents that cause disease.


Understanding what it means to be HIV positive is relatively simple -- either you are infected with the virus or you aren't -- but how do you understand AIDS?

AIDS, which stands for "Acquired Immune Deficiency Syndrome" is a way of describing a whole group of symptoms and diseases associated with the damage HIV does to the immune system. As an HIV infection progresses, there is ongoing damage to immune defense cells and the body becomes increasingly less able to fight off infections. This means that individuals with advanced HIV disease are susceptible to infections that don't show up in people with healthy immune systems. In fact, HIV and AIDS were initially recognized because of outbreaks of rare diseases and cancers that had not previously been seen in large numbers in the U.S.

Such infections are known as opportunistic infections because they take advantage of the weakened ability of an HIV positive individual to fight off disease. The difference between AIDS and HIV is that a person is said to have AIDS, as opposed to simply being HIV positive, when either the numbers of specific types of cells in their immune system drop below a certain level or when they develop one of a specific group of diseases that are designated as opportunistic infections.

It is important to know that a person can live with HIV for many years without developing AIDS or any symptoms of HIV infection. In fact, due to the fact that highly effective treatment options are increasingly available, many people with HIV live long, healthy lives without any signs of immune system dysfunction. However, appropriate treatment is essential for long-term health and well-being for people with HIV. That is why it is important to be regularly tested for the virus. Even if a person does not know they are infected, however, they can still transmit the virus to other people through unprotected sex and other risky behaviors that directly expose other people to their blood, semen, breast milk, and other potentially infectious bodily fluids. HIV is not spread through casual contact.

Pitchenik AE, Fischl MA, Dickinson GM, Becker DM, Fournier AM, O'Connell MT, Colton RM, Spira TJ. Opportunistic infections and Kaposi's sarcoma among Haitians: evidence of a new acquired immunodeficiency state. Ann Intern Med. 1983 Mar;98(3):277-84.

Schroff RW, Gottlieb MS, Prince HE, Chai LL, Fahey JL. Immunological studies of homosexual men with immunodeficiency and Kaposi's sarcoma. Clin Immunol Immunopathol. 1983 Jun;27(3):300-14.

What is AIDS? from the CDC

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