Immunogenicity and Safety Study of Infanrix Hexa in Healthy Infants Born to Mothers Vaccinated With Boostrix™ During Pregnancy or Immediately Post-delivery

Inclusion Criteria: * Subjects' parent(s)/Legally Acceptable Representative(s) \[LAR(s)\] who, in the opinion of the investigator, can and will comply, with the requirements of the protocol (e.g. completion of the diary cards, return for follow-up visits). * Written informed consent obtained from the parent(s)/LAR(s) of the subject prior to performing any study specific procedure. * A male or female between, 6 and 14 weeks of age (including 6 weeks and up to and including 14 weeks and 6 days of age) at the time of the first vaccination. * Healthy subjects as established by medical history and clinical examination before entering into the study. * Born to a mother enrolled in study 116945 \[DTPA (BOOSTRIX)-047\]. * Medically stable\* prematurely born infants, born after a gestation period of 27-36 weeks may be enrolled in the study at the discretion of the investigator. * Medically stable refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study vaccine. Exclusion Criteria: * Child in care * Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting at birth prior to the first vaccine dose. For corticosteroids, this will mean prednisone ≥0.5mg/kg/day, or equivalent. Inhaled and topical steroids are allowed. * Administration of long-acting immune-modifying drugs at any time during the study period (e.g. infliximab). * Administration of any chronic drug therapy to be continued during the study period. * A vaccine not foreseen by the study protocol administered during the period starting from 30 days before each dose of vaccine and ending 30 days after\*, with the exception of inactivated influenza vaccine and other vaccines given as a part of the national/regional immunisation schedule, that are allowed at any time during the study period. * In case an emergency mass vaccination for an unforeseen public health threat (e.g.: a pandemic) is organised by the public health authorities, outside the routine immunisation program, the time period described above can be reduced if necessary for that vaccine provided it is licensed and used according to its SPC or package insert (PI) and according to the local governmental recommendations and provided a written approval of the Sponsor is obtained. * Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product (pharmaceutical product or device). * Previous vaccination against Hib, diphtheria, tetanus, pertussis, pneumococcus, and/or poliovirus since birth. * History of Hib, diphtheria, tetanus, pertussis, pneumococcal, poliovirus and hepatitis B diseases. * Any confirmed or suspected immunosuppressive or immunodeficient condition including severe combined immunodeficiency disease (SCID), based on medical history and physical examination (no laboratory testing required). * Family history of congenital or hereditary immunodeficiency. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine. * Major congenital defects * Serious chronic illness. * History of any neurological disorders or seizures. * Acute disease and/or fever at the time of enrolment. * Fever is defined as temperature ≥37.5°C/99.5°F for oral, axillary or tympanic route, or ≥38.0°C/100.4°F for rectal route. * Subjects with a minor illness (such as mild diarrhoea, mild upper respiratory infection) without fever may, be enrolled at the discretion of the investigator. * Administration of immunoglobulins and/or any blood products during the period starting at birth before the first dose of study vaccines or planned administration during the study period. * Hypersensitivity to latex.