Study to Evaluate the Immunogenicity and Reactogenicity of a Booster Dose of GSK2036874A Vaccine in Healthy Toddlers

The purpose of the study is to assess the immunogenicity and safety of three formulations of GSK Biologicals' GSK2036874A vaccine compared to Zilbrix™/Hib and Poliorix™ vaccines administered concomitantly, when administered as a single booster dose to healthy poliovirus-primed toddlers aged 12-24 months.

The study will be conducted in a partially double-blinded manner. The study will be double-blinded with respect to the three GSK2036874A formulation groups and open-label with respect to the Control Group.

Eligibility Criteria:
Inclusion Criteria:

* A male or female subject, between and including 12 and 24 months of age at the time of booster vaccination.
* Subjects who have received three doses of polio vaccine as primary vaccination along with the routine vaccinations indicated during the first year of life.
* Subjects who the investigator believes that their parent(s)/Legally Acceptable Representative (s) can and will comply with the requirements of the protocol.
* Written informed consent obtained from the parent(s)/Legally Acceptable Representative (s) of the subject.
* Healthy subjects as established by medical history and clinical examination before entering into the study.

Exclusion Criteria:

* Use of any investigational or non-registered product other than the study vaccine(s) within 30 days preceding the booster dose of study vaccine, or planned use during the study period.
* Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the booster dose.
* Administration of a vaccine not foreseen by the study protocol within 30 days prior to booster vaccination, or planned administration during the active study period (up to Visit 2).
* 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 product.
* History of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and/or Haemophilus influenza type b diseases.
* Previous booster vaccination against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B or H. influenzae diseases.
* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
* A family history of congenital or hereditary immunodeficiency.
* Major congenital defects or serious chronic illness.
* History of neurologic disorders or seizures.
* History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccines.
* Administration of immunoglobulins and/or any blood products within the three months preceding the booster dose or planned administration during the study period.
* Occurrence of transient thrombocytopenia or neurological complications following an earlier immunisation against diphtheria and/or tetanus.
* Child in care.
* Occurrence of any of the following adverse events after a previous administration of a diphtheria-tetanus-pertussis vaccine:

  * encephalopathy of unknown aetiology occurring within seven days following previous vaccination with pertussis-containing vaccine,
  * fever \>= 40 °C within 48 hours of vaccination not due to another identifiable cause,
  * collapse or shock-like state within 48 hours of vaccination,
  * convulsions with or without fever, occurring within 3 days of vaccination.
* Acute disease and/or fever at the time of enrolment.

  * Fever is defined as temperature \>= 37.5°C on oral, axillary or tympanic setting, or \>= 38.0°C on rectal setting.
  * Subjects with a minor illness without fever may, be enrolled at the discretion of the investigator.
* Other conditions which, in the opinion of the investigator, may potentially interfere with interpretation of study results.