Assess the Immune Response Following Primary Vaccination With GSK Biologicals' Tritanrix™-HepB/Hib-MenAC vs Tritanrix™-HepB/Hiberix™ Given at 6,10 & 14 Wks of Age to Infants Who Received Hepatitis B Vaccine at Birth

Inclusion criteria: * Healthy infants aged 7 days +/- 3 days old born to mothers who are tested as seronegative for HIV \& HBsAg, written informed consent obtained from the parents, born after a gestation period of 36 to 42 weeks. Exclusion criteria: * Known exposure to diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b and/or meningococcal disease since birth. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on physical examination. * A family history of congenital or hereditary immunodeficiency. * Major congenital defects or serious illness. * Any neurologic disorders or seizures. * Acute disease at the time of enrolment. * Administration of immunoglobulins and/or any blood products since birth or planned administration during the study period. * A birth dose of hepatitis B vaccine given outside the frame of this study.