Immunogenicity and Safety of Sanofi Pasteur's Combined Vaccine Given as a Three-Dose Primary Series at 2, 3,4 Months of Age and Followed by a Booster Dose Given at 16 to 17 Months of Age in Vietnamese Infants Who Previously Received a Dose of Hepatitis B Vaccine at Birth or Within 1 Week After Birth

The purpose of this study is to describe the immunogenicity and safety of Sanofi Pasteur's DTaP-IPV-Hep B-PRP-T fully liquid combined hexavalent vaccine (Hexaxim®) administered at 2, 3, and 4 months of age and at 16 to 17 months of age in infants and toddlers who received a dose of Hep B vaccine at birth or within 1 week after birth. Primary Objective: * To describe the safety profile after each and all doses of Sanofi-Pasteur's DTaP-IPV-Hep B-PRP-T combined vaccine in Vietnamese infants and toddlers. Secondary Objective: * To demonstrate the non-inferiority of the immune response to all antigens induced by the study vaccine in Vietnamese infants one month after the third dose in a 3-dose primary series with the immune response to all antigens induced by the same study vaccine outside Vietnam. * To evaluate the immunogenicity of the study vaccine one month after the 3-dose primary series. * To describe the persistence of all antibodies before receipt of the booster vaccination. * To evaluate the immunogenicity of the study vaccine one month after the booster.