Long-term persistence of immunity against hepatitis B in 7-8 years old children after hepatitis B vaccination.

•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.

•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