along such characteristics as the disparities in risk behaviors and/or patterns of risk behaviors would greatly assist targeting and tailoring prevention interventions.
Regular, geographically detailed information about the prevalence of HIV (and, as useful surrogates, hepatitis B and C) could help guide priorities in mounting public health initiatives.
Improved measurements of injection drug use and sexual risk behaviors are needed. Such measures should include information on: (1) patterns of drug use (e.g., drug type, route of administration, frequency of use, source of needles, patterns of reuse of needles); (2) direct and indirect sharing behavior; (3) patterns of sexual contacts (e.g., heterosexual, homosexual, frequency, number of patterns) and activities (e.g., receptive anal sex); (4) sexually transmitted diseases; and (5) drug and sexual social networks.
Better understanding of certain biological and social parameters is needed, including the relative efficiency of different transmission routes, the kinetics, and the relative efficiency of known transmission routes (i.e., direct and indirect sharing).
There is an urgent need to identify the key determinants of illicit drug injection at both the individual and the community levels. In particular, it is important to conduct etiologic studies of the transition from noninjection to injection drug use.
Most individuals who inject illicit drugs begin this behavior in late adolescence or early adulthood (Gerstein and Green, 1993; Newcomb and Bentler, 1988; Chen and Kandel, 1995). Moreover, as mentioned in Chapter 2, a substantial number of those who reported having injected a drug in the past year were between the ages of 12 and 25. Chapter 3 also shows that needle exchange programs do not recruit a sizable number of young injectors. This highlights the need for recruiting study cohorts of younger individuals as part of ongoing efforts to further our understanding of injection drug use and improve AIDS prevention strategies. This is especially urgent because some studies have shown that seroconversion typically occurs during the early stages of injection drug use after initiation has occurred (Nicolosi et al., 1992; Moss et al., 1994; Nelson et al., in press).
Chapter 4 of this report highlighted the severity of the drug abuse problem in our society. Injection drug use ruins the lives of users and of those close to them. HIV and AIDS have only worsened the situation. Coping with these public health problems is much more likely to succeed if we fully understand them. Moreover, critical to the effective implementation of HIV