Safety, Immunogenicity and Reactogenicity of Recombinant Hepatitis B Vaccine (Adjuvanted & New Formulation) and Engerix™-B

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: * Pregnancy or lactation. * Positive titres for anti HBs antibody. * Any vaccination against hepatitis B in the past. * Any previous administration of MPL. * Elevated serum liver enzymes. * History of significant and persisting hematologic, hepatic, renal, cardiac or respiratory disease. * Axillary temperature \> 37.5°C at the time of injection. * Any acute disease at the moment of entry. * Chronic alcohol consumption. * Any treatment with immunosuppressive or immunostimulant therapy. * Any chronic drug treatment, 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. * Simultaneous administration of any other vaccine(s). * Administration of any immunoglobulin during the study period. * Simultaneous participation in any other clinical trial.