original New York City and Washington, D.C., case studies presented in Chapter 3.
For a more detailed discussion of the legal environment surrounding needle exchange programs, the reader is referred to the following publications: Gostin (1991a, 1991b, 1993) and Pascal (1988).
Contaminated needles and syringes are a primary mechanism for transmitting HIV among injection drug users. According to some researchers, "it would be difficult to design a system better suited to promote the transmission of a blood-borne infection" (Friedland and Klein, 1987). The causal role of sharing1 used injection equipment in transmitting diseases has been well documented for some time (Brecher, 1941; Louria, 1967; Cherubin, 1967; Centers for Disease Control and Prevention, 1993) and for a variety of blood-borne diseases, such as hepatitis and bacterial endocarditis (Selwyn and Alcabes, 1994). Sharing contaminated injection equipment has also been shown to be the primary mechanism of HIV transmission among injection drug users (Chaisson et al., 1987; Chitwood et. al., 1990; Marmor et al., 1987; Schoenbaum et al., 1989; Friedland et al., 1985; Vlahov et al., 1990).
Given the clear risk of transmission of HIV infection when used drug equipment is shared, why do injection drug users engage in this activity? Various investigators have attempted to shed light on that important question. The sharing of drug paraphernalia is a dynamic behavioral process that is a function of multiple factors and their interactions:
demographic factors, such as age, gender, maturity of drug career, and treatment history;
paraphernalia availability, both in the community at large and at the time of injection;
perception of risk of arrest and of HIV infection and other diseases;
situational/contextual variables, such as the use of shooting galleries;
group norms and social networks, involving the cohesion of groups; and
drug of choice (e.g., cocaine, heroin, amphetamine, polydrug use), which is also related to intensity of use (i.e., frequency of injection).