Immunogenicity & Reactogenicity of HBV-MPL Vaccine and Engerix™-B in Healthy Adults Following 2 Different Schedules

Inclusion Criteria: * Between 18 and 40 years old. * Written informed consent will have been obtained from the subjects. * Good physical condition as established by physical examination and history taking at the time of entry. * Female participants will avoid becoming pregnant during the study period and they will have been on a contraceptive program for at least 2 months before entry. Exclusion Criteria: * Positive titres for anti hepatitis B antibodies. * Any vaccination against hepatitis B in the past. * Elevated serum liver enzymes. * History of significant and persisting hematologic, hepatic, renal, cardiac or respiratory disease. * Axillary temperature \> 37°C at the time of injection. * Any acute disease at the moment of entry. * Chronic alcohol consumption. * Any chronic drug treatment, including any treatment with immunosuppressive drugs, which in the investigator's opinion, precludes inclusion into the study. * History of allergic disease likely to be stimulated by any component of the vaccine. * Administration of any other vaccine(s) or any immunoglobulin during the study period. * Simultaneous participation in any other clinical trial.