Evaluate Immune Response Approximately 5 to 6 Years After Receiving Different Formulations of GSK Bio Hep B Vaccine

Evaluate the Anti-HBs Antibody Persistence, in Subjects Who Received GSK Biologicals' Preservative-free or Thiomersal-free Engerix™-B or Engerix™-B Containing Thiomersal, Approximately 5 to 6 Yrs Earlier

To evaluate the persistence of antibodies against hepatitis B, approximately 5 to 6 years after the first dose of the hepatitis B in the primary vaccination study.

All subjects who participated in the primary vaccination study, where subjects who received GSK Biologicals' hepatitis B vaccine and who will consent to participate in this long-term follow-up study, approximately 5 to 6 years after the primary vaccination study. The study will be conducted in only 3 centres out of the 4 centres in the primary vaccination study.

Inclusion Criteria:

• Subjects should have participated in the primary study and should have received the first primary dose of vaccination more than five years ago and less than six years ago before blood sampling in this long-term follow-up study.
• Written informed consent obtained from the subject for the long-term follow-up.