Inclusion Criteria:

• Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol.
• A male or female of 7 to 8 years of age (from and including the 7th birthday up to but excluding the 9th birthday) at the time of enrolment.
• With documented evidence of previous vaccination with three consecutive doses of Engerix™-B in Germany
• Written informed consent obtained from the parents or guardians of the subject at the time of enrolment.
• Healthy subjects as established by medical history and clinical examination before entering into the study.

Exclusion Criteria:

• Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product
• Evidence of previous hepatitis B booster vaccination since administration of the third dose of Engerix™-B vaccine.
• History of or intercurrent hepatitis B disease.
• Hepatitis B vaccination at birth.
• Planned administration/administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before HBV vaccine challenge and ending 30 days after.
• Administration of immunoglobulins and/or any blood products within the three months preceding HBV vaccine challenge or planned administration during the study period.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the HBV vaccine challenge.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination