Grant: CIHR New Investigator

Injection drug use remains a primary source of HIV transmission globally, and people who inject drugs (PWID) have been shown to play a key role in the initiation of others into injecting. However, no interventions to prevent injecting initiation are proven effective. Importantly, ongoing exposure to injecting increases the risk that street youth and other 'at-risk' populations might initiate injecting, and data suggest that the majority of non-injectors are initiated into injecting by PWID. Reducing the exposure of street youth to injecting is therefore likely to reduce their risk of initiation into injection. This multicountry, mixed methods project will therefore investigate whether a range of interventions and factors that influence injecting among PWID (opioid substitution therapy, supervised injection facilities, stable housing, incarceration environments, public injecting, and gender) may also influence the risk that they initiate others into injecting. This study will seek to: 1) determine how often PWID initiate others into injecting; 2) assess factors potentially influencing the risk that PWID initiate others into injecting; 3) investigate drug scene roles (i.e., drug dealer) that increase the risk that PWID might initiate others into injecting; and 4) test the impact of an existing structural or biomedical intervention on the risk that PWID will initiate others into injecting. To accomplish this, we will conduct a multi-site study of 3,050 PWID across North America and France employing quantitative and qualitative data from five separate ongoing observational studies of PWID (San Diego, STAHR; Tijuana, El Cuete; Vancouver, VIDUS/ARYS; Toronto, HHiT, Bordeaux/Marseille/Paris, COSINUS). This project is the first study to investigate structural approaches to reducing HIV risk by preventing injecting initiation. This novel approach addresses a major gap in HIV prevention programming.