A common practice among injecting drug users is the sharing of needles and other injection equipment. Sharing needles allows diseases to spread from one user to another. HIV, the virus that causes AIDS, has been reported among injecting drug users in sixty countries, from all continents except Antarctica, and from both industrialized and developing nations. The Centers for Disease Control and Prevention (CDC) estimates that injection drug use directly accounts for 25 percent of infections among men and women. This figure does not include cases of HIV infection with an indirect relation to injection drug use, such as those having sexual contact with people who acquired the virus through injection drug use.

Once HIV becomes well established in a population of injecting drug users, their sexual partners are at risk of contracting the virus. In addition, pregnant women can pass the virus on to developing...