Human Immunodeficiency Virus (HIV)
HIV is the virus that causes AIDS (acquired immunodeficiency syndrome), a life-threatening disease. Initially, an HIV infection may cause no symptoms or cause non-specific, flu-like symptoms that resolve after a short time period. If the infection is not detected and treated, eventually symptoms of AIDS emerge and begin to progressively worsen. Over time, HIV destroys the immune system and leaves a person's body vulnerable to debilitating infections.
In the 40 states with confidential HIV reporting, more than 10,200 people ages 30-45 were newly diagnosed with HIV in 2009, the last year for which the U.S. Centers for Disease Control and Prevention (CDC) has statistics. Gay and bisexual men are the group most heavily affected by HIV, followed by injection drug users. African Americans and Hispanics/Latinos are also disproportionately affected. An estimated 1.2 million people in the U.S. are living with HIV infection, and as many as 20% of those with the infection are not aware of it and may pass the virus on to others.
HIV is spread in the following ways:
- By having unprotected sex with an infected partner
- By sharing needles or syringes (such as with intravenous injection drug abuse)
- During pregnancy or birth; if a pregnant woman is infected with HIV, the virus can be passed to and infect her developing 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 beginning in 1985 in the U.S. 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.
Why Get Screening?
Screening for HIV infection has become routine health care in the United States and is an important part of wellness and prevention. This is because diagnosis early in the course of infection leads to timely, effective treatment that slows progression to AIDS. Early diagnosis also has important benefits for others and society at large. If you learn you are positive for HIV, you can also modify your behavior so you don't expose others to your infected blood or body fluids, thus preventing further spread of the disease. If a woman is pregnant and her doctor knows she is HIV-positive, treatment can prevent her passing the infection to her child. If an HIV screening test shows you're not infected, you can take steps to avoid infection.
Know Your Risk
Several situations put you at high risk of contracting HIV:
- You've had unprotected sex with more than one partner; having a sexually transmitted disease (STD) appears to make people more susceptible to and at higher risk for acquiring HIV infection during sex with infected partners.
- You're a man who has had sexual contact with another man.
- You have exchanged sex for money or drugs or had anonymous sex.
- You use or used injection drugs and are likely to have shared unsterilized needles.
- You have an HIV-positive sexual partner.
- You have had sex with anyone who falls into one of the categories listed above or are uncertain about your sexual partner's risk behaviors.
How often you are tested should depend on your activities and sexual contacts. For example, during a long-term, truly monogamous sexual relationship, you may want just one test. However, if you or your partner have had sexual contact with more than one person since then, your risk of infection is greater. If you or a person with whom you've had sexual contact (even unwanted sexual contact) engaged in some risky behavior, you have even more reason to be tested.
Different types of antibody tests may be used for HIV screening. Combination tests that detect the HIV antibody and the p24 antigen may be performed to increase the likelihood that HIV infection is detected as soon as possible after exposure occurs.
Various options are available for getting tested:
- A blood or oral sample can be collected in a doctor's office or a local clinic and sent to a laboratory for testing. In these same settings, a rapid test may available in which results are generated in about 20 minutes.
- A home collection kit approved by the U.S. Food and Drug Administration (FDA) is available for HIV antibody testing. This allows a person to take a sample at home and then mail it to a testing center. Results are available over the phone, along with appropriate counseling.
- In July 2012, the FDA approved for marketing the first HIV test for home use. The testing kit is the same as that used in many doctors' offices and clinics in which an oral sample is collected for testing and results are available in about 20 minutes. Though the home test is convenient, it has limitations. It is less sensitive than a blood test so the home test may miss some cases of HIV that a blood test would detect and it is not as accurate when it is performed at home by a lay person compared to when it is performed by a trained health care professional. Care must be taken to avoid errors when performing the test. (For more, see the article on Home Testing, Avoiding Errors.)
Screening tests have limitations so it is important to remember that:
- Although a healthy person who has no HIV antibodies will get a negative result, a negative screening test means only that there is no evidence of disease at the time of the test. If you have increased risk of HIV infection but negative screening results, it is very important to get screening tests on a regular basis.
- Antibodies can be detected about 2 to 8 weeks after exposure to the virus. If exposure to the virus is more recent, then antibody levels may be too low to detect and it may be necessary to repeat testing at a later time with another antibody test or combination HIV antibody/antigen test.
- A positive screening test is not a diagnosis. A positive result must be followed by a second antibody test that is different from the first test, sometimes the Western blot test or an antibody test that detects different antigens and differentiates between HIV-1 and HIV-2, to establish a diagnosis.
- The U.S. Centers for Disease Control and Prevention (CDC) recommends that everyone 13 to 64 years old have an HIV screening test at least once, regardless of gender, sexual orientation, ethnic group, and risk of getting the disease. The CDC recommends getting tested annually if you are at increased risk of contracting an HIV infection.
- The American College of Physicians agrees with the CDC that everyone aged 13 to 64 be offered an HIV screening test in health care settings. It also recommends that the frequency of repeat screening should be determined by doctors on an individual basis.
- The United States Preventive Services Task Force (USPSTF) recommends that all people ages 15 to 64 undergo screening for HIV. As for how often, the Task Force says a reasonable approach is one-time testing for all people ages 15 to 64 and at least annual screenings for those at very high risk of HIV, such as males who have sex with males, IV drug users, and in settings with high HIV-positive prevalence, such as STD clinics, drug treatment centers, correctional facilities, and clinics that serve the homeless. Adults at increased but not very high risk may be screened less frequently than every year, such as every three to five years. The Task Force points out that risk is "on a continuum" and health professionals should use their own discretion in deciding how frequently to test people for HIV.
- For recommendations specific to pregnant women, see the article on Pregnancy.
Aside from these recommendations, certain individuals should get tested and learn their status. These include:
- People diagnosed with hepatitis, tuberculosis (TB) or an STD
- 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 he or she may have been exposed
Talk to your health care provider
Don't be surprised if a health care provider, in any care setting, asks you or your partner to consent to an HIV screening test, in keeping with CDC recommendations. Routine HIV testing (which you can decline or "opt out" of) prevents feelings of embarrassment or shame from becoming obstacles to crucial health care. Those infected find out sooner and can then get treatment when it works best and take steps to protect the health of sex partners and even their unborn children. If your health care provider does not bring up sexual health topics, you can ask for an HIV screening test or a risk assessment. You can also use confidential services to obtain testing or counseling.
Resources & Links
For confidential information, you can call the STDs and HIV/AIDS hotline of the CDC: 800-232-4636.
To find a testing site near you, visit National HIV and STD Testing Resources
MedlinePlus Interactive Health Tutorial: HIV and AIDS
Mayo Clinic: HIV/AIDS - Preparing for your appointment
CDC: Questions and Answers for the General Public: Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health Care Settings
HIV Testing Basics for Consumers
Sources Used in Current Review
U.S. Centers for Disease Control and Prevention. Basic Statistics. Available online at http://www.cdc.gov/hiv/topics/surveillance/basic.htm#hivaidsage through http://www.cdc.gov. Last reviewed August 2011. Accessed May 1, 2012.
U.S. Centers for Disease Control and Prevention. Report. Diagnoses of HIV Infection and AIDS in the United States and Dependent Areas, 2009. Available online at http://www.cdc.gov/hiv/surveillance/resources/reports/2009report/ through http://www.cdc.gov. Last updated February 6, 2011. Accessed April 27, 2012.
U.S. Centers for Disease Control and Prevention. Questions and answers for the general public: revised recommendations for HIV testing of adults, adolescents, and pregnant women in healthcare settings. Last modified 22 Jan 2007. Available online at http://www.cdc.gov/hiv/topics/testing/resources/qa/qa_general-public.htm through http://www.cdc.gov. Accessed April 2012.
U.S. Centers for Disease Control and Prevention. HIV Testing Basics for Consumers. Available online at http://www.cdc.gov/hiv/topics/testing/resources/qa/index.htm through http://www.cdc.gov. Last reviewed April 9, 2010. Accessed May 2012.
(July 2005, Amended April 2007) U.S. Preventive Services Task Force. Summary of Recommendations, Screening for HIV. Available online at http://www.uspreventiveservicestaskforce.org/uspstf/uspshivi.htm through http://www.uspreventiveservicestaskforce.org. Accessed April 2012.
Screening for HIV: U.S. Preventive Services Task Force Recommendation Statement, DRAFT. Available online at http://www.uspreventiveservicestaskforce.org/draftrec.htm#consider through http://www.uspreventiveservicestaskforce.org. Accessed January 4, 2013.