HIV infection


HIV infection is a condition caused by the human immunodeficiency virus (HIV). The condition gradually destroys the immune system, which makes it harder for the body to fight infections.

This article provides a general overview. For more detailed information, see:

Alternative Names

Human immunodeficiency virus infection


The human immunodeficiency virus (HIV) can be spread by the following:

Rare ways the virus may be spread include:

Blood banks and orang donor programs screen donors, blood, and tissues thoroughly to prevent the risk of infection. HIV is NOT transmitted to a person who DONATES blood or organs. People who donate organs are never in direct contact with people who receive them. Likewise, a person who donates blood is never in contact with the person receiving it. In all these procedures, sterile needles and instruments are used.

HIV infection is NOT spread by:

People at highest risk for getting HIV include:

See also: AIDS


People who become infected with HIV may not have any symptoms for up to 10 years, but they can still pass the infection to others. After you come in contact with the virus, it can take up to 3 months for a blood test to show that you have HIV.  

Symptoms related to HIV are usually due to a different infection in the body. Some symptoms related to HIV infection include:

Note: Many people have no symptoms when they are diagnosed with HIV.

Exams and Tests

The HIV ELISA and HIV Western blot tests detect antibodies to the HIV virus in the blood. Both tests must be positive to confirm an HIV infection. Having these antibodies means you are infected with HIV.

A complete blood count (CBC) and white blood cell differential may also show abnormalities.

A lower-than-normal CD4 cell count may be a sign that the virus is damaging your immune system.


Doctors usually recommend medicine for patients who are committed to taking all their medications and have a CD4 count below 500 cells/mm3 (which is a sign that of a weakened immune system). Some people, including pregnant women and people with kidney or neurological problems related to HIV, may need treatment regardless of their CD4 count.

It is extremely important for people with HIV to take all doses of their medications, otherwise the virus may become resistant to the drugs. Therapy always involves a combination of antiviral drugs. Pregnant women with HIV infection are treated to reduce the chance of transmitting HIV to their babies.

People with HIV infection need to become educated about the disease and treatment so that they can be active participants in making decisions with their health care provider.

Support Groups

See: AIDS - support group

Outlook (Prognosis)

HIV is a chronic medical condition that can be treated, but not yet cured. There are effective ways to prevent complications and delay, but not always prevent, progression to AIDS.

Almost all people infected with HIV will develop AIDS if not treated. However, there is a small group of people who develop AIDS very slowly, or never at all. These patients are called long-term nonprogressors.

Possible Complications

When to Contact a Medical Professional

Call your health care provider if you have had a possible or actual exposure to AIDS or HIV infection.



Quinn TC. Epidemiology of human immunodeficiency virus infection and acquired immunodeficiency syndrome. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 392.

Sterling TR, Chaisson RE. General clinical manifestations of human immunodeficiency virus infection (including the acute retroviral syndrome and oral, cutaenous, renal, ocular, metabolic, and cardiac diseases. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 121.

Review Date: 5/30/2012
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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