The primary mode of HIV transmission in IVDUs is sharing of contaminated needles and syringes. Sharing of injection paraphernalia (“works”) is commonplace among IVDUs and is reinforced by the cultural economic and legal environment in the IVDU community. The risk of HIV transmission is highest among IVDUs who share needles and use drugs that are injected more often, such as cocaine. HIV is frequently transmitted from IVDUs to their sexual partners through both heterosexual and homosexual activity, and ultimately, the virus may be transmitted to their children via perinatal exposure. Many cases of heterosexual transmission, including transmission from prostitutes, are associated with intravenous drug use.

Prevention
The primary mode of preventing HIV transmission in IVDUs is to prevent the use of intravenous drugs in the first place. Education programs that are culturally sensitive and geared to young audiences have the best chance of preventing drug use. Access to treatment centers is the best approach for those individuals already using IV drugs.

For those IVDUs who do not wish to seek treatment or who are unable to gain access to treatment, the most effective way to prevent HIV infection is to avoid sharing needles and works. Where works are in short supply, needles and syringes should be cleaned after each use, preferably with readily accessible virucidal cleansers such as chlorine bleach (diluted 1:100). Some communities have adopted programs that provide free needles and syringes for IVDUs. Voluntary HIV testing and outreach programs that rigorously maintain confidentiality can be effective in reducing transmission to sexual partners of IVDUs. In order to be effective, antibody testing should be combined with intensive pretest and post-test counseling.

The efficacy of many community programs is limited, however, by cultural barriers, including lack of trust, fear of prosecution, misconceptions regarding the prevalence of HIV infection within the local drug-using population, and the use of ineffective language in delivering anti-HIV messages by program staff. When combined with the relative paucity of IV drug treatment resources, HIV education among IVDUs which ultimately results in behavioral changes represents the most challenging HIV prevention goal.