Higher syringe coverage is associated with lower odds of HIV risk and does not increase unsafe syringe disposal among syringe exchange program clients.

OBJECTIVE: To determine if adequate syringe coverage --"one shot for one syringe"--among syringe exchange program (SEP) clients is associated with injection-related HIV risk behaviors and syringe disposal.
DESIGN: HIV risk assessments with 1577 injection drug users (IDUs) recruited from 24 SEPs in California between 2001 and 2003. Individual syringe coverage was calculated as a proportion of syringes retained from SEP visits to total number of injections in the last 30 days.
RESULTS: Participants were divided into four groups based on syringe coverage: <50%, 50-99%, 100-149%, and 150% or more. In multivariate logistic regression, SEP clients with less than 50% syringe coverage had significantly higher odds of reporting receptive syringe sharing in the last 30 days (adjusted odds ratio [AOR]=2.3; 95% confidence interval [CI]=1.4, 3.6) and those with 150% or more coverage had lower odds of reporting receptive syringe sharing (AOR=0.5; 95%CI=0.3, 0.8) as compared to SEP clients with adequate syringe coverage of 100-149%. Similar associations were observed for other main outcomes of distributive syringe sharing and syringe re-use. No differences in safe syringe disposal were observed by syringe coverage.
CONCLUSIONS: Individual syringe coverage is strongly associated with safer injection behaviors without impacting syringe disposal among SEP clients. Syringe coverage is a useful measure for determining if IDUs are obtaining sufficient syringes to lower HIV risk.