All Canadian provinces and territories have immunization programs to prevent hepatitis B virus infection. Youth immunized with three doses of Hepatitis B Vaccine (HBV) as infants may lose protection 15 or more years after vaccination.

This study will enroll 320 youth who were immunized with HBV as infants to measure their residual immunity. Participants lacking antibody protection will be challenged with a dose of HBV vaccine to determine if they have residual immune memory (ability to recall antibody protection), which is sufficient for protection if present. Those unable to respond to the booster challenge will need to be revaccinated. If a significant number of participants have lost protection, a routine booster dose may be needed at a younger age. Options for program changes will be explored by mathematical modeling of benefits and costs. This clinical trial will better inform decision-making about the need for booster doses of the vaccine after infant vaccination.

Team Members:

• David Scheifele, Project Lead, Univesity of British Columbia
• Mark Loeb, McMaster University
• Meena Dewar, University of British Columbia
• Babak Pourbohloul, University of British Columbia
• Marc Brisson, Laval University
• Gaston De Serres, Laval University
• Mel Krajden, University of British Columbia
• Soren Gantt, Child and Family Research Institute
• Julie Bettinger, University of British Columbia
• Jane Buxton, British Columbia Centre for Disease Control
• Steven Hawken, Ottawa Hospital Research Institute
• Monika Naus, University of British Columbia
• Michelle Pinto, Child and Family Research Institute