Syringe Sharing and HIV Incidence Among Injection Drug Users and Increased Access to Sterile Syringes

Objectives. We assessed the effects of syringe exchange program (SEP) policy on rates of HIV risk behavior and HIV incidence among injection drug users. Methods. Using a multivariate generalized estimating equation and Cox regression methods, we examined syringe borrowing, syringe lending, and HIV incidence among a prospective cohort of 1228 injection drug users in Vancouver, British Columbia. Results. We observed substantial declines in rates of syringe borrowing (from 20.1% in 1998 to 9.2% in 2003) and syringe lending (from 19.1% in 1998 to 6.8% in 2003) following SEP policy change. These declines coincided with a statistically significant increase in the proportion of participants accessing sterile syringes from nontraditional SEP sources (P<.001). In multivariate analyses, the period following the change in SEP policy was independently associated with a greater than 40% reduction in syringe borrowing (adjusted odds ratio [AOR]=0.57; 95% confidence interval [CI]=0.49, 0.65) and lending (AOR=0.52; 95% CI =0.45, 0.60), as well as declining HIV incidence (adjusted hazard ratio=0.13; 95% CI=0.06, 0.31). Conclusions. Widespread syringe distribution appears to be a more effective SEP policy than do more restrictive SEP policies that limit syringe access. Efforts should be made to ensure that SEP policies and program design serve to maximize rather than hinder syringe access. (Am J Public Health. 2010;100: 1449-1453. doi:10.2105/AJPH.2009.178467)