Evaluation of Antibody Persistence and Immune Memory Against the Hepatitis B Antigen in Previously Vaccinated Children

Inclusion Criteria: * Subjects who the investigator believes that their parents/Legally acceptable representative) can and will comply with the requirements of the protocol should be enrolled in the study. * A male or female aged 11-12 years at the time of study entry (from and including the 11th birthday until and excluding the 13th birthday). * Written informed consent obtained from the parent or Legally Acceptable Representative of the subject. * Study procedures will be explained to subjects and depending on their understanding, optional informed assent will be sought at the discretion of the investigator. * Written informed assent obtained from the subject in addition to the informed consent signed by the parent(s)/ Legally Acceptable Representative (s). * Healthy subjects as established by medical history and clinical examination before entering into the study. * Subjects who have received all three doses of Infanrix hexa or Engerix-B in the primary study 217744/031 (NCT01457495). * Female subjects of non-childbearing potential may be enrolled in the study. * Female subjects of childbearing potential may be enrolled in the study, if the subject: * has practiced adequate contraception for 30 days prior to vaccination, and * has a negative pregnancy test on the day of vaccination, and * has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series. 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. * Child in care. * Use of any investigational or non-registered product drug or vaccine) other than the study vaccine within 30 days preceding the challenge dose of HBV vaccine, or planned use during the study period. * Receipt of hepatitis B (containing) vaccine after vaccination in the primary study 217744/031 (NCT01457495). * History of hepatitis B disease. * Planned administration/administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before and ending 30 days after the HBV vaccine challenge dose. * Administration of immunoglobulins and/or any blood products within the three months preceding the challenge dose of HBV vaccine or planned administration during the study period. * Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the challenge dose of HBV vaccine. * 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. * Fever is defined as temperature ≥ 37.5°C (99.5°F) on oral, axillary or tympanic setting * Subjects with a minor illness without fever may be enrolled at the discretion of the investigator.