Human immunodeficiency virus (HIV) is a virus that attacks the white blood cells called helper T cells (CD4). These cells are part of the immune system. They fight off infections and disease. As a result, an HIV infection can leave you vulnerable to severe illnesses.
AIDS is a late stage of HIV infection. It reflects severe damage to the immune system. One or more opportunistic infections will also likely exist. Opportunistic infections are a type of infection that only occur in people with compromised immune systems.
HIV is spread through contact with HIV-infected blood or other body fluids. This includes semen, vaginal fluid, and breast milk. The infection may be the result of HIV-1 or HIV-2 virus.
AIDS is caused by the destruction of T cells. The destruction is caused by the HIV virus.
HIV destroys white blood cells vital to the immune system.
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HIV is most commonly spread through:
Rarely, HIV can be spread through:
Factors that may increase your chance of HIV infection include:
HIV infection increases the chances of getting AIDS.
HIV may not cause symptoms for a number of years.
After these initial symptoms pass, there may be no symptoms for months to years. The following symptoms may occur over the years:
If left untreated, HIV infection progresses to AIDS. This may happen when the number of T helper cells fall below certain levels and opportunistic infections arise. People with AIDS are susceptible to many health complications. These may include:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. To confirm a diagnosis of HIV infection, your doctor will run tests. These may include:
Medications can prevent, delay, or control the development of AIDS in many people infected with HIV.
Antiviral drugs are often given in combination. Categories of these drugs include:
People who have developed AIDS may be given other medications to help fight infections that are more likely to occur with a weak immune system. These may include antibiotics or antifungal medications.
To help reduce your chance of HIV infection:
If you are a healthcare worker or work in a correctional facility, take these steps:
If you live in a household with an HIV-infected person:
If you are infected with HIV, take these steps to prevent spreading HIV to others:
American Foundation for AIDS Research
Centers for Disease Control and Prevention
AIDS Committee of Toronto
Canadian AIDS Society
2015 Sexually transmitted diseases treatment guidelines. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/std/tg2015/default.htm. Updated March 9, 2016. Accessed May 31, 2016.
Acute HIV infection. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 27, 2016. Accessed May 31, 2016.
Bailey RC, Moses S, Parker CB, et al. Male circumcision for HIV prevention in young men in Kisumu, Kenya: A randomised controlled trial. Lancet. 2007;369(9562):643-656.
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.
Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. AIDS Info website. Available at: https://aidsinfo.nih.gov/contentfiles/lvguidelines/adultandadolescentgl.pdf. Accessed May 31, 2016.
HIV/AIDS: The basics. AIDS info website. Available at: https://aidsinfo.nih.gov/education-materials/fact-sheets/19/45/hiv-aids--the-basics. Updated September 15, 2015. Accessed May 31, 2016.
HIV infection. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 23, 2016. Accessed May 31, 2016.
HIV transmission risk. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/hiv/law/pdf/HIVtranmsmision.pdf. Updated July 2012. Accessed August 14, 2014.
Montaner JS. Treatment as prevention: A double hat-trick. Lancet. 2011;378(9787):208-209.
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/nchhstp/Default.htm. Updated May 24, 2016. Accessed May 31, 2016.
Pre-exposure prophylaxis (PrEP). AIDS website. Available at: https://www.aids.gov/hiv-aids-basics/prevention/reduce-your-risk/pre-exposure-prophylaxis/index.html. Updated January 29, 2016. Accessed May 31, 2016.
Preventing transmission of HIV. AIDS info website. Available at: https://aidsinfo.nih.gov/education-materials/fact-sheets/20/48/the-basics-of-hiv-prevention. Updated August 2012. Accessed May 31, 2016.
Post-exposure prophylaxis (PEP). AIDS website. Available at: https://www.aids.gov/hiv-aids-basics/prevention/reduce-your-risk/post-exposure-prophylaxis. Updated September 21, 2015. Accessed May 31, 2016.
Rey D, Krebs M, Partisani M, Hess G, et al. Virologic response of zidovudine, lamivudine, and tenofovir disoproxil fumarate combination in antiretroviral-naive HIV-1-infected patients. J Acquir Immune Defic Syndr. 2006;43(5): 530-534.
Ross LL, Parkin N, Gerondelis P, et al. Differential impact of thymidine analogue mutations on emtricitabine and lamivudine susceptibility. J Acquir Immune Defic Syndr. 2006;43(5):567-570.
Testing for HIV. AIDS info website. Available at: https://aidsinfo.nih.gov/education-materials/fact-sheets/19/47/hiv-testing. Updated September 24, 2015. Accessed May 31, 2016.
3/8/2007 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Auvert B, Taljaard D, Lagard E, et al. Randomized, controlled intervention trial of male circumcision for reduction of HIV infection risk: the ANRS 1265 Trial. PLoS Med. 2005;2(11):e298.
2/21/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Mallal S, Phillips E, Carosi G, et al. HLA-B5701 screening for hypersensitivity to abacavir. N Engl J Med. 2008;358(6):568-579.
6/11/2010 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Del Romero J, Castilla J, Hernando V, Rodríguez C, García S. Combined antiretroviral treatment and heterosexual transmission of HIV-1: Cross sectional and prospective cohort study. BMJ. 2010:c2205.
10/8/2014 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: British Association of Sexual Health and HIV (BASHH) recommendations on testing for sexually transmitted infections in men who have sex with men. Available at: http://www.bashh.org/documents/BASHH%20Recommendations%20for%20testing%20for%20STIs%20in%20MSM%20-%20FINAL.pdf. Updated 2014. Accessed May 31, 2016.
Last reviewed May 2016 by David Horn, MD Last Updated: 5/31/2016