Human Immunodeficiency Virus

The Human Immunodeficiency Virus (HIV) causes an individual’s immune system to weaken and lose its ability to fight off infections and cancers. After developing a number of these infections or reaching a certain blood count level, an HIV-positive person is diagnosed with Acquired Immunodeficiency Syndrome (AIDS).

HIV is present in blood, semen, vaginal secretions, and breast milk. It is transmitted through unprotected anal, vaginal, and oral sex with an infected person; through contaminated needles or syringes used to inject drugs; or from an infected mother to her newborn during childbirth or breast-feeding.

HIV is not transmitted through such casual contact as hugging, shaking hands, sharing food, using the same eating utensils, drinking from the same glass, sitting on public toilets, or touching door knobs.

Signs and Symptoms:

  • There are no symptoms of HIV infection.
  • The average time between HIV infection and AIDS is eight to 11 years.
  • Over time, HIV causes the body to develop opportunistic infections or cancers normally controlled by a healthy immune system.
  • AIDS symptoms are usually those of the opportunistic infection or cancer. These include fever, chills and sweats, chronic fatigue, appetite or weight loss, muscle and joint pain, long-lasting sore throat, swollen lymph nodes, diarrhea, yeast infections, and skin sores.
  • Opportunistic infections that most frequently affect individuals with AIDS include Kaposi's sarcoma, Pneumocystis carinii pneumonia (PCP), tuberculosis, meningitis, and Herpes simplex infections.



  • HIV infection is diagnosed through blood tests. It can also be diagnosed through urine tests and an oral fluid test taken from the inside of the mouth.
  • Tests that determine HIV infection look for antibodies produced by the body to fight the virus. Most people will develop such antibodies between 25 days and three months after infection (though in rare cases it can take up to six months). Although it is possible to test earlier, the CDC recommends testing three months after the last possible exposure.
  • Testing sites may provide pre- and post-test counseling for those who want it. They may also provide either anonymous (no name given) or confidential (name given only to doctor) testing. Some states require that doctors report positive results to state health departments. Individuals should check to determine procedures at individual sites.
  • For more information about HIV tests and test sites, individuals should contact the CDC National AIDS Hotline at 1-800/342-2437 (English), 1-800/344-7432, (Spanish), or 1-800/243-7889 (TTY) or the CDC’s National HIV Testing Resources webpage at




  • There is no cure or vaccine for HIV or AIDS. There are, however, new combinations of drugs (called “cocktails”) that allow people to live with the infection or HIV/AIDS for longer periods of time.


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  • National Data - CDC's "A Glance at the HIV/AIDS Epidemic" fact sheet:
  • At the end of 2003, it was estimated that between 1,039,000 and 1,185,000 persons in the United States were living with HIV/AIDS.
  • In 2005, 38,096 cases of HIV/AIDS in adults, adolescents, and children were diagnosed in the 33 states with updated reporting systems.
  • The CDC estimates that approximately 40,000 people in the United States become infected with HIV each year.
  • In 2005, the largest portion of HIV/AIDS diagnoses were for men who have sex with men (MSM), followed by adults and adolescents infected through heterosexual contact.


Data by Sex:

  • CDC's HIV/AIDS Among Women fact sheet:
  • In 2005, almost three quarters of HIV/AIDS diagnoses were for male adolescents and adults.
  • In 2002, HIV infection was the 5th leading cause of death among all women ages 35-44 and the 6th leading cause of death among all women ages 25-34.
  • In 2004, heterosexual contact was the source of 78% of new infections in women.


Data by Race/Ethnicity:

  • CDC's HIV/AIDS Among African Americans, HIV/AIDS Among Hispanics, HIV/AIDS Among Asian/Pacific Islanders, and HIV/AIDS Among American Indians and Alaskan Natives fact sheets:
  • In 2005, African Americans, who make up approximately 12% of the U.S. population, accounted for almost half of the estimated number of HIV/AIDS cases diagnosed.
  • Most African-American men living with HIV/AIDS were through sexual contact with other men, followed by injection drug use and high-risk heterosexual contact.
  • Most African-American women living with HIV/AIDS were exposed through high-risk heterosexual contact, followed by injection drug use.
  • In 2004, Hispanics accounted for 18% of new diagnoses reported in the 35 states and territories (includes the U.S. Virgin Islands and Guam) with updated reporting systems.
  • Most Hispanic living with HIV/AIDS men were exposed through sexual contact with other men, followed by injection drug use and heterosexual contact. Most Hispanic women living with HIV/AIDS were exposed through heterosexual contact, followed by injection drug use.
  • At the end of 2004, less than 1% of the estimated 462,792 persons living with HIV infection or AIDS in the 35 states and territories with updated reporting systems were Asians and Pacific Islanders.
  • At the end of 2004, 77% of Asians and Pacific Islanders living with HIV/AIDS were men, 22% were women, and 1% were children.
  • The numbers of HIV and AIDS diagnoses for American Indians and Alaska Natives represent less than 1% of the total number of HIV/AIDS cases reported to the CDC. However, when population size is taken into account, this population in 2004 was ranked 3rd in rates of AIDS diagnoses, after African Americans and Hispanics.
  • In the 33 states with updated reporting systems, women accounted for 29% of the HIV/AIDS diagnoses among American Indians and Alaska Natives between 2001 and 2004.


Data by Age:

  • CDC's HIV/AIDS and Youth fact sheet:
  • In 2004, 13% of new infections occurred in young people ages 13-24.
  • In 2004, 55% of new infections among young people occurred in African- American youth.
  • In the 7 cities that participated in CDC's Young Men's Survey during 1994-1998, 14% of African American young men who have sex with men (MSM) and 7% of Hispanic MSM ages 15-22 were infected with HIV.
  • The number of young people living with AIDS increased by 42% to 5,457 in 2004 from 7,761 in 2000.
  • During 2001-2004, in the 33 states with updated reporting systems, 62% of the 17,824 young people ages 13-24 diagnosed with HIV/AIDS were males and 38% were females.


State Data:



Epidemiology of HIV/AIDS Among Young Adults
Maria C Rangel, et al., "Epidemiology of HIV and AIDS among Adolescents and Young Adults in the United States," Journal of Adolescent Health, 39.2 (August 2006), 156-163.

At the end of 2003, 7074 adolescents and young adults, ages 13-24 years at the time of diagnosis, were living with AIDS in the United States.

National case surveillance data for young people ages 13-24 revealed that the burden of HIV and AIDS falls most heavily upon the Southern region of the United States and disproportionately upon black and Hispanic youth.

Findings highlight the need for intensified HIV-prevention efforts within minority communities and among men who have sex with men as well as strengthened efforts to encourage at-risk youth to get tested for HIV.

The full text of this article may be obtained online for free through the Journal of Adolescent Health