Primary Vaccination With Either Synflorix™ or Prevenar 13™ or Both Vaccines and Booster Vaccination With Synflorix™

Two-dose Primary Vaccination With Either GSK Biologicals' 10-valent Pneumococcal Vaccine (Synflorix™) or Pfizer's Prevenar 13™ or Both Vaccines Followed by a Booster Dose of Synflorix™

The primary aim of this study is to assess the reactogenicity of Synflorix vaccine and Prevenar 13 vaccine after primary vaccination at 2 and 4 months of age with either Synflorix or Prevenar 13 vaccine or Prevenar 13 and Synflorix, respectively. In addition, this study aims at assessing the safety, reactogenicity, immunogenicity and antibody persistence (approximately 8-11 months following primary vaccination) of the Synflorix vaccine and Prevenar 13 vaccine after primary vaccination at 2 and 4 months of age with either Synflorix or Prevenar 13 vaccine or Prevenar 13 and Synflorix, respectively. This study also aims at assessing the safety, reactogenicity and immunogenicity of the Synflorix vaccine when given as a booster dose at 12-15 months of age following primary vaccination at 2 and 4 months of age with either Synflorix vaccine or Prevenar 13 vaccine or Prevenar 13 and Synflorix respectively.

This study is partially blinded as the primary phase will be conducted in an observer-blind method and booster phase will be open method.

Inclusion Criteria:

• Subjects who the investigator believes that parent(s)/Legally Acceptable Representative(s) [LAR(s)] can and will comply with the requirements of the protocol.
• A male or female between, and including, 6-12 weeks 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 after a gestation period of at least 36 weeks.
• Written informed consent obtained from the parent(s)/LAR(s) of the subject.

Exclusion Criteria:

• Child in care.
• Use of any investigational or non-registered product other than the study vaccines within 30 days preceding the first dose of study vaccines, or planned use during the entire study period.
• Chronic administration of immunosuppressants or other immune-modifying drugs since birth or planned use during the study.
• 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.
• 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 study vaccine.
• Major congenital defects or serious chronic illness.
• History of any seizures or progressive neurological disease.
• Administration of immunoglobulins and/or blood products since birth or planned use during the study.
• Acute disease and/or fever at the time of enrolment.
• Previous vaccination or planned vaccination during the study with any pneumococcal vaccine.