• Vaccine series completion
  

• Hepatitis B Surface Antibodies
  
• Reduction of Risk Behavior (Sexual, Drug, & Health)
  
• Vaccine attitudes
  
• Hepatitis A Antibodies
  

This is a research trial consisting of a cross-sectional screening study and a prospective cohort study (randomized, 2x2 factorial design). The primary aim of the study is to evaluate the effects of immunization setting and outreach worker support on young IDU's adherence to a multiple dose immunization schedule with a combined HAV and HBV vaccine. Secondarily, the study will 1) explore the feasibility of a remote immunization network and web-based vaccine registry to improve immunization coverage of transient young IDU, 2) examine the effect of hepatitis C virus infection in vaccine effectiveness, and 3) assess behavior change and vaccine attitudes in young IDU participating in a preventive vaccine trial.

Subjects in the screening study complete an interview, receive counseling and testing for HIV, HAV, HBV and HCV, and return in one week for test results and risk reduction counseling. Subjects eligible for the cohort study receive their first immunizations at enrollment and then are randomized to receive subsequent vaccines at either a set of syringe exchange programs or at a public health adult immunization clinic. Subjects also are randomized to receive vaccine reminders from an outreach worker or no outreach worker support. Each subject receives a total of 4 immunizations over 6 months. Follow up visits include interviews, counseling, and viral testing. Study participation is for 12 months.