Human immunodeficiency virus (HIV) is a virus that attacks a part of the immune system. It targets white blood cells called CD4 (T cells). They are needed to fight off infections and other diseases. Low levels of CD4 cells make it harder for the body to stop or control infections and diseases.
AIDS is a late stage of HIV infection. It is a sign of severe damage to the immune system. This level of damage can lead to infections that do not usually occur in healthy people. It also allows the growth of some cancers.
HIV is spread through contact with HIV-infected body fluids. This includes blood, semen, vaginal fluid, and breast milk.
HIV is most commonly spread through:
Rarely, HIV can be spread through:
Factors that may increase your chance of HIV infection include:
HIV may not cause problems for a number of years.
Early symptoms may appear 1 to 2 months after an infection. They may last a couple of weeks. Early symptoms may include:
There may be no additional symptoms for months to years. Symptoms that do occur over the years may include:
If left untreated, HIV infection may progress to AIDS. This may happen when the number of CD4 cells fall below certain levels. The body is more vulnerable to infections such as:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests to confirm a diagnosis of HIV infection include:
There is no cure for HIV at this time. The goal of treatment is to control HIV. Treatment, called antiretroviral treatment (ART), can:
Antiviral medicine can stop the virus from multiplying and harming the immune system. However, it cannot get rid of the virus. Once treatment is stopped the virus will likely grow and spread again. Antiviral medicines are often given in combination. Categories of these medicines include:
Medicine needs to be taken as directed for best results. The care team can help to address side effects or cost problems. Blood tests will be done on a regular schedule. They can show if treatment is working and look for possible side effects.
The doctor may recommend some steps to prevent new infections. This will depend on your CD4 count and other risk factors. Options may include:
Chronic diseases can impact your day to day life. There are many support options that may help with these challenges. Options include:
There are steps you can take to decrease the risk of spreading HIV to others:
AMFAR—The Foundation for AIDS Research
Centers for Disease Control and Prevention
AIDS Committee of Toronto
Canadian AIDS Society
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Gray RH, Kigozi G, Serwadda D, et al. Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial. Lancet. 2007;369(9562):657-666.
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Last reviewed January 2021 by EBSCO Medical Review Board David L. Horn, MD, FACP Last Updated: 2/18/2021