Persistence of Immunity Against Hepatitis B in 12-13 Year Old Adolescents After Infant Hepatitis B Vaccination

Inclusion Criteria: * Subjects who the investigator believes that their parent(s)/Legally Accepted representative (LAR(s)) can and will comply with the requirements of the protocol. * A male or female of 12 to 13 years of age at the time of enrolment. * With documented evidence of previous vaccination with three consecutive doses of Engerix-B in Germany: with the first two doses received by 9 months of age and the third dose received by 18 months of age. * Written informed consent obtained from the parent(s) or LAR(s) of the subject at the time of enrolment. * Written informed assent obtained from the subject in addition to the informed consent signed by the parent(s)/LAR(s). * Healthy subjects as established by medical history and clinical examination before entering into the study. * Female subjects of non-childbearing potential may be enrolled in the study. * Females of childbearing potential at the time of study entry must have a negative pregnancy test prior to administration of the dose of vaccine and are required to be abstinent or to use adequate contraceptive precautions for one month prior to vaccination. Subjects are required to agree to continue such precautions for two months after vaccination. 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 hepatitis B disease. * Hepatitis B vaccination at birth. * Adolescents living in institutional care. * 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 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 (no laboratory testing required). * Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the challenge dose of study vaccine, or planned use during the study period. * Pregnant or lactating female. * Female planning to become pregnant or planning to discontinue contraceptive precautions. * Known hypersensitivity to any component of the HBV vaccine or evidence of hypersensitivity after previous immunisation with a vaccine containing the hepatitis B component. * Acute disease and/or fever at the time of enrolment.