A Study to Assess the Anamnestic Immune Response in Healthy 4 to 7 Year-old Children After a Primary Vaccination Series With Either HEXAVAC® or INFANRIX®-HEXA

Inclusion Criteria: * Healthy child of 4 to 7 years of age of either gender, * Child vaccinated with 2 doses of HEXAVAC® during the first 6 months of life and with a 3rd dose of HEXAVAC® before the end of the second year of life or Child vaccinated with 2 doses of INFANRIX®-HEXA during the first 6 months of life and with a 3rd dose of INFANRIX®-HEXA before the end of the second year of life, * Informed consent form signed by the parent(s) or by the legal representative. * Parent(s) or legal representative able to understand and comply with the study procedures. Exclusion Criteria: * Any recent (\<=3 days) history of febrile illness prior to vaccination, * Receipt of more than 3 doses of any Hepatitis B containing vaccine, either alone or in any combination, * History of clinical or serological-confirmed diagnosis of infection due to hepatitis B, * History or current close contact with known carriers of hepatitis B virus, * Prior known sensitivity/allergy to any component of the study vaccines, * Any known blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms affecting the haematopoietic and lymphatic systems, * Any severe thrombocytopenia or any other coagulation disorder that would contraindicate intramuscular injection, * Any immune impairment or humoral/cellular deficiency or depressed immunity, * Any recent (\<=30 days) long-term (\>=14 days) administration of systemic corticosteroids given daily or on alternate days at \>=20 mg/day prednisone equivalent or scheduled administration through Visit 2, * Any receipt (\<=3 months) of immunoglobulins or blood-derived products, or scheduled administration through Visit 2, * Any recent (\<=14 days) receipt of an inactivated vaccine or scheduled administration through Visit 2, * Any recent (\<=28 days) receipt of a live vaccine or scheduled administration through Visit 2