title: A randomized controlled trial of monetary incentives vs. outreach to enhance adherence to the hepatitis B vaccine series among injection drug users.
abstract: BACKGROUND
  Injection drug users (IDUs) are at high-risk for hepatitis B virus (HBV) and HIV. Due to concerns about non-adherence to multi-dose vaccine regimens however, IDUs are severely under-immunized against HBV and have been excluded from phase III trials of multi-dose candidate HIV vaccines in the United States.
  
  
  METHODS
  Through a randomized controlled trial, we compared the effectiveness of monetary incentives versus outreach to improve IDUs' adherence to the 3-dose hepatitis B vaccine. In 1998-1999, HBV-susceptible IDUs were recruited from San Francisco streets. Eligible participants received their first dose of vaccine and were randomized to either receive monthly monetary incentives (n=48) or maintain weekly contact with an outreach worker (n=48) during the 6-month vaccine series.
  
  
  RESULTS
  All 3 doses of vaccine were received by 33 (69%) of IDUs in the monetary incentive arm and 11 (23%) in the outreach arm (odds ratio=13.8; 95% confidence interval, 2.9, 128; P<0.0001). In a multivariate model, receiving monetary incentives was independently associated with vaccine completion (AOR=10.3; 95% CI=3.7, 29.0).
  
  
  CONCLUSIONS
  Among IDUs, monetary incentives are superior to outreach in achieving adherence to the multi-dose hepatitis B vaccine series. Monetary incentives may be adapted to future multi-dose candidate HIV vaccine trials in IDUs.
authors.affiliation: Urban Health Study, Department of Family and Community Medicine, University of California San Francisco, San Francisco, CA 94110, USA. karens@itsa.ucsf.edu
authors.forename: Karen H
authors.initials: KH
authors.lastname: Seal
authors.forename: Alex H
authors.initials: AH
authors.lastname: Kral
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lorvick
authors.forename: Alex
authors.initials: A
authors.lastname: McNees
authors.forename: Lauren
authors.initials: L
authors.lastname: Gee
authors.forename: Brian R
authors.initials: BR
authors.lastname: Edlin
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D003159:Community-Institutional Relations; D016001:Confidence Intervals; D005260:Female; D017325:Hepatitis B Vaccines / Q000191:economics* / Q000627:therapeutic use; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009042:Motivation; D016017:Odds Ratio; D010349:Patient Compliance / Q000523:psychology / Q000706:statistics & numerical data*; D015819:Substance Abuse, Intravenous / Q000188:drug therapy / Q000191:economics* / Q000523:psychology
chemical_list: D017325:Hepatitis B Vaccines