Immunogenicity and Safety of GSK Biologicals' HBV-MPL Vaccine and Engerix™-B in Healthy Adults (15-40 Yrs).

Inclusion Criteria: * Age: between 15 and 40 years old. * Good physical condition as established by clinical examination and history taking at the time of entry. * Female participants who are at risk to become pregnant will be on a contraceptive programme if necessary during the study period. * Written informed consent obtained from the subjects aged between 18 and 40 and from the parents/tutor when the subjects are aged between 15 and 17 years. Exclusion Criteria: * Positive titres at screening for anti-HBs antibodies. * Elevated serum liver enzymes. * History of significant and persisting hematologic, hepatic, renal, cardiac or respiratory disease. * Any acute disease at the moment of entry. * Chronic alcohol consumption. * Hepatomegaly, right upper quadrant abdominal pain or tenderness. * 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. * Simultaneous participation in any other clinical trial. * Previous vaccination with a hepatitis B vaccine. * Previous vaccination with an MPL containing vaccine. * Administration of immunoglobulins in the past 6 months and during the whole study period * Simultaneous vaccination one week before and one week after each dose of the study vaccine