Abstract
The cumulative epidemiologic literature indicates that many injecting drug users (IDUs) initiate injection as a mode of drug administration during late adolescence or early adulthood. Recent studies have shown that IDUs are often exposed to viral infections relatively early in the course of injection, highlighting the importance of understanding this initiation process for both epidemiology and prevention. Epidemiologic evidence similarly suggests that at least some youth populations, most notably young men who have sex with men (YMSM), are at substantial risk for exposure to HIV and other sexually transmitted diseases (STDs) from early sexual activity. Despite the importance of this issue for both epidemiology and prevention, however, surprisingly little information is available on the social course of injection initiation, including the individual, social, or ecological factors that might mitigate or exacerbate transmission risks within the critical phase of early injection drug use. Similarly, we know little about the ways that YMSM and other high-risk youth understand risk, the kinds of exchanges and relationships in which they participate in the context of initiating sexual activity, or how drug use is operant in these exchanges and early sexual experiences. In this article, we explore key dimensions of the early initiation of injection and sexual risk, and discuss how a social network approach might be instrumental in understanding the social course of drug injection and sexual activities among youth and young adult populations.