Concentrations given as geometric mean concentration (GMC) expressed as milli-international unit per millilitre (mIU/mL).

Solicited local symptoms assessed include pain, redness and swelling. Any was defined as occurrence of the specified solicited local symptom regardless of its intensity. Grade 3 pain was defined as pain that prevented normal everyday activities. Grade 3 swelling was greater than 100 millimeters (mm) i.e. \>100mm.

A seropositive subject was defined as a vaccinated subject who had a anti-HAV antibody titres ≥ 33 mIU/ml.

Concentrations given as GMC expressed as mIU/mL. NOTE: There was a change of assay kit at Year 15 time-point, thus for the sake of bridging, blood samples corresponding to Year 14 were re-tested with ChemiLuminescence ImmunoAssay (CLIA). From Year 11 to Year 14, anti-HBs antibody concentrations were tested with ELISA with cut-off of 3.3 mIU/mL while, Year 14\* onwards, anti-HBs antibody concentrations were tested with the CLIA with cut-off of 6.2 mIU/mL.

A seropositive subject was defined as a vaccinated subject who had anti-HB antibody titres ≥ 1 mIU/mL. NOTE: There was a change of assay kit at Year 15 time-point, thus for the sake of bridging, blood samples corresponding to Year 14 were re-tested with ChemiLuminescence ImmunoAssay (CLIA)

A seroprotected subject was defined as a subjects with the anti-HBs titres ≥ 10 mIU/mL. NOTE: There was a change of assay kit at Year 15 time-point, thus for the sake of bridging, blood samples corresponding to Year 14 were re-tested with ChemiLuminescence ImmunoAssay (CLIA)

A SAE was defined as any untoward medical occurrence that: resulted in death, was life threatening, required hospitalization or prolongation of hospitalization, resulted in disability/incapacity or was a congenital anomaly/birth defect in the offspring of a study subject. Any was defined as occurrence of any symptom regardless of intensity grade or relation to vaccination and related was an event assessed by the investigator as causally related to the study vaccination.

Solicited general symptoms assessed included fatigue, headache, malaise, nausea, vomiting and fever. Any was defined as any solicited general symptom reported irrespective of intensity and relationship to vaccination.

An AE is any untoward medical occurrence in a clinical investigation subject, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product.

A SAE was defined as any untoward medical occurrence that: resulted in death, was life threatening, required hospitalization or prolongation of hospitalization, resulted in disability/incapacity or was a congenital anomaly/birth defect in the offspring of a study subject. Any was defined as occurrence of any symptom regardless of intensity grade or relation to vaccination and related was an event assessed by the investigator as causally related to the study vaccination.

Anti-HAV antibody concentration cut-off value assessed was ≥ 15 milli-International Units per milliliter (mIU/mL).

Anti-HBs antibody concentration cut-off value assessed was ≥ 3.3 mIU/mL.

An SAE is any untoward medical occurrence that: results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/ incapacity, is a congenital anomaly/birth defect in the offspring of a study subject, or may evolve into one of the outcomes listed above.

Immune response was defined as: * anti-hepatitis B surface antigen (anti-HBs) antibody concentration equal or above to 10 milli-international units per milliliter (mIU/mL) at 1 month post-challenge dose in subjects seronegative at the pre-challenge time-points * at least a 4-fold increase in anti-HBs antibody concentrations at 1 month post-challenge dose in subjects seropositive at the pre-challenge time-points.

Serious adverse events (SAEs) assessed include medical occurrences that result in death, is life threatening, require hospitalization or prolongation of hospitalization, result in disability/incapacity or are a congenital anomaly/birth defect in the offspring of a study subject.

Solicited local symptoms assessed include pain, redness and swelling. Solicited general symptoms assessed include fatigue, fever, gastrointestinal symptoms and headache.

Unsolicited adverse event (AE) covers any AE reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms.

Geometric mean concentration for anti-HAV antibodies expressed as Milli-International Units per milliliter (mIU/mL)

Geometric mean concentration for anti-HBs antibodies expressed as Milli-International Units per milliliter (mIU/mL).

Any subjects becoming seronegative for anti-HAV antibodies (i.e. titres \< 15 mIU/ml) at any long term time point, were to receive an additional vaccine dose administered between 6 to 12 months after Year 5 time point.

Subjects losing seroprotective anti-HBs antibody titres (i.e. titres \< 10 mIU/ml) at any long term time point, received an Engerix challenge dose. The table presents the geometric mean concentrations for anti-HBs antibodies, expressed as Milli-International Units per milliliter (mIU/mL).