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Human Immunodeficiency Virus

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Also known as: HIV; AIDS; Acquired Immunodeficiency Syndrome

What is HIV?

HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immunodeficiency syndrome). By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers. People diagnosed with AIDS may get life-threatening diseases called opportunistic infections, which are caused by microbes such as viruses, bacteria, fungi, or parasites. These infections do not usually make healthy people sick. Those with HIV/AIDS are also at an increased risk of developing certain cancers, neurological disorders, and a variety of other conditions.

Currently, the Centers for Disease Control and Prevention (CDC) estimates that about 50,000 people in the U.S are newly infected with HIV each year, that 1.2 million people in the U.S. are living with HIV infection, and that as many as 20% of those with the infection are not aware of it and can pass the virus on to others. In 2009, the year with the most current statistics, over 17,000 people with AIDS died, and almost 600,000 have died since the beginning of the epidemic, according to the CDC.

In 2010, the World Health Organization (WHO) estimated that worldwide as many as 2.7 million people would be newly infected with HIV, 1.8 million would die of AIDS-related illnesses, and that 34 million people were living with HIV.

HIV can be spread the following ways:

  • By having unprotected sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex. Having a sexually transmitted disease (STD) such as syphilis, genital herpes, chlamydia, gonorrhea, or bacterial vaginosis appears to make people more susceptible to and at higher risk for acquiring HIV infection during sex with infected partners.
  • By sharing needles or syringes (such as with intravenous injection drug abuse), which can be contaminated with very small quantities of blood from someone infected with the virus.
  • During pregnancy or birth. Approximately one-quarter to one-third of all untreated pregnant women infected with HIV will pass the infection to their babies. HIV also can be spread to babies through the breast milk of mothers infected with the virus. If the mother is treated with one or multiple antiretroviral therapies (three or more are referred to as highly active antiretroviral therapy: HAART) during pregnancy, she can significantly reduce the chances of passing the infection to her baby.
  • Through contact with infected blood.
  • In the U.S. today, because of screening blood for transfusion and heat-treating techniques and other treatments of blood derivatives, the risk of getting HIV from transfusions is extremely small. However, before donated blood was screened for evidence of HIV infection, and before treatments were introduced to destroy HIV in some blood products, such as factor 8 and albumin, HIV was transmitted through transfusion of contaminated blood or blood components. In areas of the world where donated blood is not routinely screened or treated for HIV, there is still risk of contracting the disease through this mode of transmission.

Several organizations recommend routine screening for HIV. The CDC, American College of Physicians (ACP), and HIV Medicine Association (HMA) recommend that anyone between the ages of 13 and 64 be screened for HIV at least once.

For additional details on screening recommendations, see the articles for Teens, Young Adults, Adults, Adults 50 and Up, as well as Pregnancy and Newborns

Annual screening is advised for those at high risk for HIV and is recommended when an individual:

  • Has had unprotected sex with more than one partner since the last HIV test
  • Is a man who has had sex with another man
  • Has used street drugs by injection, especially when sharing needles and/or other equipment
  • Has exchanged sex for drugs or money
  • Has a HIV-positive sex partner
  • Has had sex with anyone who falls into one of the categories listed above or is uncertain about their sexual partner's risk behaviors

Certain individuals should get at least a one-time test, even if they are not between the ages of 13 and 64, and learn their status. These include:

  • People diagnosed with hepatitis, tuberculosis (TB) or a sexually transmitted disease
  • People who received a blood transfusion prior to 1985 or had a sexual partner who received a transfusion and later tested positive for HIV
  • A health care worker with direct exposure to blood on the job
  • Any individual who thinks they may have been exposed

To find a testing site near you, visit the National HIV and STD Testing Resources.

Certain testing centers provide either anonymous (the name is never given) or confidential (the name is given but kept private) HIV testing and counseling. The Food and Drug Administration has approved one home-testing device that allows the person tested to remain anonymous and to get confidential results. [See In the News: Testing Critical to Reducing HIV, FDA Approves Test for Home Use] People can also contact their state, county, or city health department to find out where testing may be available.

A person's HIV status, like other medical conditions and test results, is protected by the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule and cannot be shared with friends, family, or employers without written permission. HIV status may be shared with health care providers who have a "need to know" in order to treat an individual. Also, in order to determine the incidence of HIV and to provide appropriate prevention and care services, all new cases of HIV are reported to state and local health departments. As of April 2008, data from all 50 states, the District of Columbia, and 5 dependent areas (American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands) are collected using a confidential name-based reporting system.

If a person tests positive for HIV, it is important that he or she tell their health care providers as well as all sex partners and/or anyone with whom they share needles. Counseling services are often available from the clinic or health care provider that performed the test and they can help to advise the individual on who needs to know.

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