Safety and Immunogenocity Study of GSK Biologicals' Pandemic Influenza (H1N1) Candidate Vaccine in Japanese Children

Inclusion Criteria

• Subjects who the investigator believes that their parent(s)/Legally Acceptable Representative(s) (LAR) can and will comply with the requirements of the protocol.
• Japanese children, male or female, aged between 6 months and 17 years at the time of the first study vaccination.
• Written informed consent obtained from the subject's parent(s) or LAR(s) of the subject. Whenever possible, an assent should also be obtained from the subject.
• Healthy children as established by medical history and clinical examination when entering into the study (Particular attention must be exercised when dealing with patients with bronchial asthma).
• Parent/LAR with access to a consistent means of telephone contact, land line or mobile, but NOT a pay phone or other multiple-user device.
• Female subjects of childbearing potential may be enrolled in the study, if the subject: has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination, and has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series.

Exclusion Criteria

• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine within 30 days preceding the first dose of the study vaccine or planned use during the study period.
• Clinically or virologically confirmed influenza infection from May 2009 to the day of enrolment.
• Previous administration of a novel [H1N1]v vaccine.
• Administration of any vaccines within 30 days before vaccination or planned administration within the first vaccination up to blood sampling at Day 42 and within 30 days prior to blood sampling at Day 182, with the exception of seasonal influenza vaccine.
• Administration of any seasonal influenza vaccine within 14 days before vaccination on Day 0, or planned administration within the first vaccination up to blood sampling at Day 42 and within 14 days prior to blood sampling at Day 182.
• Excessive underweight or excessive obesity. (Under or upper 2-fold standard deviation of weight distribution that are corresponding age group are used as reference).
• Chronic administration of immunosuppressants or other immune-modifying drugs within three months prior to enrolment in this study or planned administration during the study period.
• Acute disease and/or fever at the time of enrolment:
• Fever is defined as temperature >= 37.5°C on oral, axillary or tympanic setting, or >= 38.0°C on rectal setting.
• Subjects with a minor illness (such as mild diarrhoea, mild upper respiratory infection) without fever may be enrolled at the discretion of the investigator.
• Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination (no laboratory testing required).
• Acute or chronic, clinically-significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by medical history and physical examination.
• Administration of immunoglobulins and/or any blood products within the three months prior to the enrolment in this study, or planned during the study.
• Any known or suspected allergy to any constituent of influenza vaccines; a history of anaphylactic-type reaction to consumption of eggs; or a history of severe adverse reaction to a previous influenza vaccine.
• History of any neurological disorder including acute disseminated encephalomyelitis and Guillain-Barré syndrome, or convulsive seizures and epilepsy.
• Any significant disorder of coagulation or treatment with warfarin derivatives or heparin. Persons receiving individual doses of low molecular weight heparin are eligible if no such doses are given in the 24 hours before a study vaccination. Persons receiving prophylactic antiplatelet medications, e.g., low-dose acetylsalicylic acid, and without a clinically-apparent bleeding tendency, are eligible
• Any conditions which, in