Immunogenicity and Safety Study of GlaxoSmithKline Biologicals' Poliorix™ Vaccine

Inclusion Criteria: * A male or female infant between, and including, 60 and 90 days of age at the time of the first vaccination. * Born after a gestation period of 36 to 42 weeks inclusive. * Subjects who the investigator believes that their parent(s)/Legally Acceptable Representative (LAR) (s) can and will comply with the requirements of the protocol. * Written informed consent obtained from the parent(s)/LAR(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 first dose of study vaccine, or planned use during the study period. * Chronic administration of immunosuppressants or other immune-modifying drugs since birth. * Administration of immunoglobulins and/or any blood products since birth or planned administration during the study period. * Administration of a vaccine not foreseen by the study protocol within 30 days prior to vaccination, or planned administration during the study period, with exception of DTP, Hib and/or hepatitis B vaccine(s). * 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. * Evidence of previous or intercurrent poliomyelitis disease or vaccination. * History of seizures or progressive neurological disease. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine(s). * Major congenital defects or serious chronic illness. * Child in care. The following condition is temporary or self-limiting, and a subject may be vaccinated once the condition has resolved and if no other exclusion criteria are met: • Current febrile illness or axillary temperature \> 37.0 ºC or other moderate to severe illness within 24 hours of study vaccine administration.