Immunogenicity and Safety Study of 1 and 2 Doses of GlaxoSmithKline (GSK) Biologicals' Meningococcal Vaccine MenACWY-TT (GSK134612) in Toddlers, Persistence up to 5 Years After Vaccination and Co-administration With Pfizer's Prevenar 13™Vaccine

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.
• A male or female between, and including, 12 and 14 months of age at the time of the first vaccination.
• 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.
• Vaccination records showing the completion of the full primary vaccination schedule with Prevenar 13 and Diphtheria, Tetanus and Pertussis (DTP) containing vaccine according to local recommendations at least 5 months before the study entry.

Exclusion Criteria

• Child in care.
• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccines within 30 days preceding the first dose of study vaccine or planned use during the study period.
• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose. For corticosteroids, this will mean prednisone 0.5 mg/kg/day, or equivalent. Inhaled and topical steroids are allowed.
• Planned administration/administration of a vaccine not foreseen by the study protocol within the period starting 30 days before and ending 30 days after the dose of vaccines, with the exception of a licensed inactivated influenza vaccine. Measles, Mumps Rubella (MMR) vaccine or Measles Mumps Rubella and Varicella (MMRV) vaccine can be co-administered with MenACWY-TT and/or Prevenar 13. A DTPa containing vaccine can be administered after the last blood sampling (at Visit 2 or 4 depending on the group).
• 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 Neisseria meningitidis.
• Previous booster vaccination against Streptococcus pneumoniae.
• Previous booster vaccination against Corynebacterium diphtheriae, Clostridium tetani and Bordetella pertussis.
• History of meningococcal disease.
• Any confirmed or suspected immunosuppressive or immunodeficient condition (congenital or secondary), including human immunodeficiency virus (HIV) infection, based on medical history and physical examination (no laboratory testing required)*
• Note: With the exception of HIV rapid testing which will be done for subjects in South Africa.
• Family history of congenital or hereditary immunodeficiency.
• History of any reaction or hypersensitivity, including to diphtheria toxoid, likely to be exacerbated by any component of the vaccines.
• Major congenital defects or serious chronic illness.
• History of any neurological disorders or seizures, including Guillain-Barré syndrome (GBS). History of a simple, single febrile seizure is permitted.
• Acute disease and/or fever at the time of enrollment.
• Administration of immunoglobulins and/or any blood products within the 3 months preceding the first dose of study vaccine or planned administration during the study period.