An Hepatitis B Vaccine Model for HIV Vaccine Trials in Drug Users

Overview

The goal of the proposed study is to use the HBV vaccine as a model for a future HIV vaccine trial, examining the efficacy of community-based outreach intervention as well as an accelerated vaccine schedule as a method for increasing acceptance/adherence with HBV vaccination protocols among not-in-treatment drug users. This study will also examine the effect of HBV vaccination coupled with community-based outreach intervention on reducing the incidence of HIV, HBV and HCV infections and the frequency of needle use and sexual risk behaviors related to these viral transmissions. A secondary purpose will be to assess the antibody response after HBV vaccination as a measurement of immunological response in drug users.

This project will evaluate an HBV vaccination program as a model for future HIV vaccine efficacy trials in a community-based study of drug users. Two components will be analyzed in an effort to increase vaccine acceptance/adherence - behavioral intervention \& an accelerated vaccine schedule. The study also will examine the effect of these variables on risk behaviors and incidence of HIV, HBV, \& HCV infections. To accomplish these objectives, we propose a randomized behavioral intervention field trial. We will enroll 1600 current cocaine or heroin users negative for HBV \& HIV markers from two closely matched, low-income, high drug endemic communities in Houston. All participants will be offered HBV vaccination and follow-up viral testing. One community will be randomly assigned to receive an outreach behavioral intervention designed to increase vaccine awareness and vaccine compliance. The other community will receive standard care. Participants electing to be vaccinated will be randomized to either a 0,1,6 month or a 0,1,2, month vaccine schedule. Groups will be followed for two years to determine rates of HBV vaccine acceptance/adherence to the 3-dose protocol. We also will measure any changes in risk behaviors \& incidence of HIV/HBV/HCV infections as well as HBV vaccine immune response, if vaccinated. Drug users are the largest group of newly diagnosed HIV cases and so creating a model for an HIV vaccine's acceptance and adherence in this population is an important public health goal. This study will serve as a model for future HIV vaccine trials and will provide information on the effectiveness of outreach programs for increasing immunization among drug users. Unless an effective model based upon empirical experience is developed, any attempt to implement a HIV vaccination program among drug users is likely to be frustrated. If HBV vaccination coupled with outreach intervention can reduce risk behaviors and decrease the incidence of HIV/HCV infection, then this study will have a tremendous impact on the current HBV/HIV/HCV prevention strategy.