Opposition to needle exchange programs has been fueled by a Vancouver study showing an association between frequent program use and elevated rates of human immunodeficiency virus (HIV) infection among injection drug users.
We evaluated possible explanations for the observed association between elevated HIV rates and frequent needle exchange attendance using a prospective observational cohort study of injection drug users in Vancouver, BC, Canada. HIV incidence rates were examined using stratified Kaplan-Meier methods and Cox proportional hazards regression.
Between May 1996 and December 2004, 1035 individuals were recruited. At 48 months after recruitment, the cumulative HIV incidence rate was 18.1% among those reporting daily needle exchange use at baseline, compared with 10.7% among those who did not report this behavior (P