Immune Response to Hepatitis B Vaccine Challenge Dose in Subjects Who Received a Primary Neonatal Hepatitis B Vaccine.

To Evaluate Immune Response to a Hepatitis B Vaccine (Engerix™-B ) Challenge Dose in Healthy Subjects Who Received GSK Biologicals' Hepatitis B Vaccine (Engerix™-B ) Approximately 20 Years Ago as Primary Vaccination at 0, 1, 2 and 12 Months.

The current study will evaluate immunological memory to hepatitis B antigen in subjects who received primary neonatal vaccination of hepatitis B vaccine (Engerix™-B ), 20 years ago in the primary study and who have anti-HBs antibody concentrations < pre-defined cut-off values at the previous long-term time point. All participating subjects will receive a challenge dose of hepatitis B vaccine. Subjects will be aged approximately 20-21 years at the time of this study. No new subjects will be recruited in this long-term follow-up study. Blood sampling will be done one month after the administration of the challenge dose. The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007.

Inclusion Criteria:

• Subjects who the investigator believes that they can and will comply with the requirements of the protocol should be enrolled in the study.
• A male or female adult who received the complete neonatal primary vaccination course of hepatitis B vaccine in primary study approximately 20 years earlier.
• Documented level of anti-HBs antibody concentrations < specified concentration at the previous long-term time point for which serological results are available for that subject.
• Written informed consent obtained from the subject.
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• If the subject is female, she must be of non-childbearing potential or if she is of childbearing potential, she must practice adequate contraception for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for 2 months after completion of the hepatitis B challenge dose.

Exclusion Criteria:

• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the hepatitis B vaccine challenge dose.
• Administration of a vaccine not foreseen by the study protocol during the study period.
• Administration of immunoglobulins and/or any blood products during the study period.
• Drug and/or alcohol abuse.