Long-Term Immune Persistence of GlaxoSmithKline Biologicals' Inactivated Hepatitis A Vaccine, Injected According to 0, 6-month Schedule

This is a long-term follow-up study at Years 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 after primary vaccination with GSK Biologicals' hepatitis A vaccine (two-dose schedule). To evaluate the long-term antibody persistence, volunteers will donate a blood sample at Years 11, 12, 13, 14,15, 16, 17, 18, 19 and 20 after the first vaccine dose of the primary vaccination course to determine their anti-hepatitis A (anti-HAV) antibody concentrations If a subject has become seronegative for anti-HAV antibodies during any of the long-term blood sampling time point (i.e. Years 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 years), he/ she will be offered an additional vaccine dose. A blood sample will be taken on the day of the additional vaccination, 14 days and one month after additional vaccination to evaluate the immune response following this vaccination. The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007 and to include an extended follow up period up to Year 20 after primary vaccination. The study has 10 phases (100576, 100577, 100578, 100579, 100580, 111028, 111029, 111030, 111031, 111032).