A Study to Evaluate Immunogenicity and Safety of GlaxoSmithKline (GSK)'s Infanrix Hexa Vaccine (DTPa-HBV-IPV/Hib) Versus MCM Vaccine BV's Vaxelis Vaccine (DTaP5-HBV-IPV-Hib) in Healthy Infants and Toddlers

Inclusion Criteria: * Subjects' parent(s)/Legally Acceptable Representative(s) (LAR\[s\]) who, in the opinion of the investigator, could and would comply with the requirements of the protocol (e.g., return for follow-up visits). * Written or witnessed/thumb printed informed consent obtained from the parent(s)/LAR(s) of the subject prior to performing any study specific procedure. * A male or female child between and including 6 and 12 weeks of age (42 to 84 days) at the time of the first vaccination. * Subject born after at least 37 weeks of gestation. * Healthy subjects as established by the investigator based on medical history and the clinical examination before entering into the study. Exclusion Criteria: * Any clinical condition that, in the opinion of the investigator, might pose any risk to the subject due to participation in the study. As with other vaccines, administration of DTPa-HBV-IPV/Hib should be postponed in subjects suffering from acute severe febrile illness. The presence of a minor infection is not a contraindication. * Known history of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and Hib diseases since birth. * History of any reaction or hypersensitivity likely to be caused or exacerbated by any excipient or active component of the vaccine(s). * Any confirmed or suspected immunosuppressive or immunodeficient condition, including malignancies, based on medical history and physical examination (no laboratory testing required). * Family history of congenital or hereditary immunodeficiency. * Major congenital defects, as assessed by the investigator. * Acute or chronic clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined via medical history including physical examination. * Medical history of neurological disorder, including seizures. * Previous vaccination for diphtheria, tetanus, pertussis, HBV, poliomyelitis, Hib diseases and previous vaccination against pneumococcal infection with pneumococcal conjugate vaccine, with the exception of a birth dose of HBV vaccine, which may have been given in accordance with local recommendations. * Use of any investigational or non-registered product (drug, vaccine, or medical device) other than the study vaccine(s) during the period starting 30 days before the first dose of study vaccine(s) (Day -29 to Day 1), or planned use during the study period. * Planned administration/administration of a vaccine not foreseen by the study protocol in the period starting 30 days before the first dose and ending 30 days after the last dose of vaccine(s) with the exception of administration of vaccines given as part of the national immunization schedule and as part of routine vaccination practice, e.g., rotavirus vaccine, that were allowed at any time during the study period. In case emergency mass vaccination for an unforeseen public health threat (e.g., a pandemic) would have been organized by public health authorities outside the routine immunization program, the time period described above could be reduced if necessary for that mass vaccination vaccine, provided this vaccine/product(s) is licensed and used according to its Product Information. * Administration of long-acting immune-modifying drugs in the period starting 30 days before the first dose and at any time during the study period. * Administration of immunoglobulins and/or any blood products or plasma derivatives from birth or planned administration during the study period. * Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first vaccine. For corticosteroids, this would mean prednisone ≥0.5 mg/kg/day (for paediatric subjects), or equivalent. Inhaled and topical steroids are allowed. * Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or would have been exposed to an investigational or a non-investigational vaccine/product (drug or medical device). * Child in care.