Monovalent H5N1 Vaccine GSK1557484A in Children 6 Months to < 18 Years of Age

This study will assess safety and immunogenicity of GSK Biologicals' H5N1 flu candidate vaccine GSK1557484A in children 6 months to \< 18 years of age.


Eligibility Criteria:
Inclusion Criteria:

* A male or female child \>= 6 months and \< 18 years of age at the time of first vaccination.
* Written informed consent obtained from the subject's parent/guardian.
* Documentation of assent for children 9 to \< 18 years of age (or as deemed mandatory by local practice).
* Satisfactory baseline medical assessment by history and physical examination
* Parent/guardian and subject access to a consistent means of telephone contact, land line or mobile, but NOT a pay phone or other multiple-user device.
* Parents/guardians and subjects who the investigator believes understand the requirements of the protocol and can and will comply with them.
* Female subjects of non-childbearing potential may be enrolled in the study.
* Female subjects of childbearing potential must

  * have practiced adequate contraception for 30 days prior to vaccination, and
  * have a negative pregnancy test on the day of each vaccination, and
  * have agreed to continue adequate contraception for 2 months after completion of the vaccination series.

Exclusion Criteria:

* Medical history of physician-confirmed infection with an H5N1 virus.
* Previous vaccination at any time with an H5N1 vaccine.
* Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the first dose of study vaccine/product, or planned use during the study period.
* Presence of significant acute or chronic, uncontrolled medical or psychiatric illness.
* Presence of neurological or psychiatric diagnoses which, although stable, are deemed by the investigator to render the potential subject or parent/guardian unable/unlikely to provide accurate safety reports.
* Evidence of current subject or parent/guardian substance abuse, including alcohol, by medical history.
* Presence of a temperature \>= 38.0ºC by any method, or acute symptoms greater than "mild" severity on the scheduled date of first dose.
* Diagnosed with cancer, or treatment for cancer, within 3 years.
* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
* Receipt of systemic glucocorticoids within 1 month prior to first dose of test article or any other cytotoxic or immunosuppressive drug within 6 months prior to first dose of test article. Receipt of any immunoglobulins and/or any blood products within 3 months of first test article administration or planned administration of any of these products during the study period.
* Any significant disorder of coagulation or treatment with warfarin derivatives or heparin.
* An acute evolving neurological disorder or history of Guillain-Barré syndrome within 6 weeks of receipt of seasonal influenza vaccine.
* Administration of an inactivated seasonal influenza vaccine within 14 days, or of a live, attenuated seasonal influenza vaccine within 30 days before the first test article dose, or of any other vaccine(s) not foreseen by the study protocol within 30 days before the first test article dose.
* Planned administration of any vaccine(s) not foreseen by the study protocol through completion of the "Day 42" visit.
* Any known or suspected allergy to any constituent of influenza vaccines or history of severe reaction to any previous influenza vaccination.
* Known pregnancy, or a positive urine pregnancy test result prior to each test article dose.
* Lactating or nursing.
* Child in care.