Reduced risk of hepatitis B and hepatitis C among injection drug users in the Tacoma syringe exchange program

Abstract

Objectives. This case-control study examined the association between syringe exchange use and hepatitis B and C in injection drug users. Methods. Case patients included 28 injection drug users with acute hepatitis B and 20 with acute hepatitis C reported to the health department in a sentinel hepatitis surveillance county; control subjects were injection drug users with no markers of exposure to hepatitis B or C (n = 38 and 26, respectively) attending health department services during the same period. Data were abstracted from clinic records. Results. Seventy-five percent of case patients with hepatitis B and 26% of control subjects had never used the exchange; similar proportions were found for the hepatitis C case and control groups. After adjustment for demographic characteristics and duration of injecting drugs, nonuse of the exchange was associated with a sixfold greater risk of hepatitis B (odds ratio [OR] = 5.5; 95% confidence interval [CI] = 1.5, 20.4) and a sevenfold greater risk of hepatitis C (OR = 7.3; 95% CI = 1.6, 32.8). Conclusions. The results suggest that use of the exchange led to a significant reduction in hepatitis B and hepatitis C in the county and may have also prevented a substantial proportion of human immunodeficiency virus infections in injection drug users.