HIV basics 

Definition
The human immunodeficiency virus (HIV) is the virus that causes AIDS.  

Number infected
The Centers for Disease Control and Prevention (CDC) estimates that there have been approximately 40,000 new infections each year since 1992.  The CDC also estimates that there were 800,000 to 900,000 persons living with HIV or AIDS in the United States at the end of 1998.  About 625,000 of them knew they were infected.⁽¹⁾ These estimates include all people with HIV/AIDS, regardless of how they were infected.  

How spread
HIV can be transmitted from one person to another when the blood, semen, vaginal fluid, or breast milk of an HIV-infected person enters another person’s body. This can occur through a vein (during injection drug use); the vagina, anus or rectum; the mouth; or through cuts and  sores.⁽²⁾

The most common ways of transmitting HIV are sexual intercourse, sharing needles or injection equipment, or during childbirth or breastfeeding.

HIV can be transmitted through a blood transfusion but that risk is quite low in the United States because all donated blood in the U.S. is tested for HIV.

HIV does not survive well in the environment, making the possibility of casual or passive transmission highly unlikely.

Unbroken human skin is an effective barrier to HIV and latex products (gloves, condoms, etc.) provide strong protection.

Footnotes

(1) Centers for Disease Control and Prevention, 1999, "Guidelines for national human immunodeficiency virus case surveillance, including monitoring for human immunodeficiency virus infection and acquired immunodeficiency syndrome." Morbidity and Mortality Weekly Report, vol. 48 (No. RR-13).

(2) Richard Sorian and Jennifer Kates, 2000, "The State of the HIV/AIDS Epidemic in America." April.  Kaiser Family Foundation. Capitol Hill Briefing Series of HIV/AIDS. Available in Adobe Acrobat.

For a list of other materials used on this website, see References.