Immunogenicity and Safety of Booster Dose of PoliorixTM Vaccine in Previously Vaccinated Toddlers

Immunogenicity and Safety of a Booster Dose of GlaxoSmithKline Biologicals' IPV (PoliorixTM) in Healthy Chinese Toddlers

This study aims to evaluate the persistence of anti-poliovirus antibodies in toddlers aged 18 months who were primed with oral polio vaccine (OPV) or inactivated polio vaccine (IPV) in the primary study. The study will also assess the immunogenicity and reactogenicity of a booster dose of IPV in subjects primed with three doses of IPV.

All subjects will also receive a booster dose of GSK Biologicals' DTPa/Hib vaccine (Infanrix+Hib) at Day 0. This vaccine will be provided as part of the local standard of care and will not be associated with any study endpoint.

Inclusion Criteria:

• Subjects who the investigator believes that their parent(s)/Legally Acceptable Representative(s) can and will comply with the requirements of the protocol.
• Subjects who received the complete three-dose primary vaccination course in study NCT01021293.
• Healthy male or female toddlers 18 to 24 months of age at the time of Visit 1 (Day 0).
• 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:

• Child in care.
• Use of any investigational or non-registered product other than the study vaccine(s) within 30 days preceding the booster dose of study vaccine(s), or planned use during the study period.
• Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to Visit 1 (Day 0).
• Administration of immunoglobulins and/or any blood products within the 3 months preceding Visit 1 (Day 0) or planned administration during the study period.
• Administration of a vaccine not foreseen by the study protocol within 30 days of Visit 1 (Day 0) or planned administration during the study period.
• 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 booster vaccination against poliomyelitis or the disease since the conclusion visit of Study NCT01021293.
• 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.
• Major congenital defects or serious chronic illness.
• Acute disease and/or fever at the time of enrolment.