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 (Engerix™-B), in the 103860/272 primary study approximately 20 years earlier.
•Documented level of anti-HBs antibody concentrations < 100 milli-international units per milliliter (mIU/ml) 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:

•Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the first dose of study vaccine, or planned use 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 hepatitis B vaccine challenge dose.
•Planned administration/ administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before the hepatitis B vaccine challenge dose and ending 30 days after.
•Subjects who received a booster dose of hepatitis B vaccine outside the context of this study between the long-term time-point at the documented level of anti-HBs antibody concentrations and the current challenge dose study visit.
•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.
•History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
•Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection.
•Acute disease at the time of enrolment.
•Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
•Administration of immunoglobulins and/or any blood products within the three months preceding the hepatitis B vaccine challenge dose or planned administration during the study period.
•Pregnant or lactating female.
•Female planning to become pregnant or planning to discontinue contraceptive precautions.