Safety and Immunogenicity Study of GSK Biologicals' Pandemic Influenza Candidate Vaccine (H1N1) (GSK2340272A)

• Humoral immune response in terms of H1N1 HI antibodies [ Time Frame: Day 0, 21, 42, Month 6, Month 6+7 Days, Month 12 and Month 18 ] [ Designated as safety issue: No ]
• Humoral immune response in terms of neutralizing antibodies (in a subset of subjects) [ Time Frame: Day 0, 21, 42, Month 6, Month 6+7 Days, Month 12 and Month 18 ] [ Designated as safety issue: No ]
• Occurrence of local and general symptoms [ Time Frame: During a 7-day follow-up period after each vaccination ] [ Designated as safety issue: No ]
• Occurrence of unsolicited symptoms [ Time Frame: During a 21-day follow-up period after the first vaccination, during a 62-day follow-up period after the second vaccination, and during a 30 day follow up period after the booster vaccination ] [ Designated as safety issue: No ]
• Occurrence of adverse events of specific interest / potential immune-mediated disorders, of serious adverse events, and of medically attended visits [ Time Frame: From the beginning up to the study end (i.e. Day 0 up to Month 12) ] [ Designated as safety issue: No ]
• Safety evaluation in terms of biochemical parameters [ Time Frame: Day 0, 21, 42, Month 6 and Month 6 + 7 Days ] [ Designated as safety issue: No ]

• Humoral immune response in terms of H1N1 HI antibodies [ Time Frame: Day 0, 21, 42, Month 6, Month 6+7 Days, Month 12 and Month 18 ] [ Designated as safety issue: No ]
• Humoral immune response in terms of neutralizing antibodies [ Time Frame: Day 0, 21, 42, Month 6, Month 6+7 Days, Month 12 and Month 18 ] [ Designated as safety issue: No ]
• Occurrence of local and general symptoms [ Time Frame: During a 7-day follow-up period after each vaccination ] [ Designated as safety issue: No ]
• Occurrence of unsolicited symptoms [ Time Frame: During a 21-day follow-up period after the first vaccination, during a 62-day follow-up period after the second vaccination, and during a 30 day follow up period after the booster vaccination ] [ Designated as safety issue: No ]
• Occurrence of adverse events of specific interest, of serious adverse events, and of medically attended visits [ Time Frame: From the beginning up to the study end ] [ Designated as safety issue: No ]
• Safety evaluation in terms of biochemical parameters [ Time Frame: Day 0, 21, 42, Month 6 and Month 6 + 7 Days ] [ Designated as safety issue: No ]

This trial is designed to assess the safety and immunogenicity of a prime-boost schedule of GSK Biologicals' investigational vaccine GSK2340272A in children aged between 3 and 17 years.

• Influenza A Virus, H1N1 Subtype
• Influenza Infection

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.
• Children, male or female, aged between 3 and 17 years at the time of the first study vaccination.
• Written informed consent obtained from the subject parent(s) or LAR(s) of the subject. Assent obtained from the subject when applicable.
• Healthy children as established by medical history and clinical examination when entering into the study.
• Parent/LAR with access to a consistent means of telephone contact, land line or mobile, but NOT a pay phone or other multiple-user.

Exclusion Criteria:

• Use of any investigational or non-registered product 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 within six months preceding the study start.
• Planned administration of any vaccine 30 days prior and 30 days after any study vaccine administration.
• 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
• Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination.
• Acute or chronic, clinically-significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by medical history and physical examination.
• Previous administration of any H1N1 A/California-like vaccine.
• Administration of immunoglobulins and/or any blood products within the three months prior to the enrolment in this study, or planned during the study.
• If the subject is female and if she is of childbearing potential, she must practice adequate contraception for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for two months after completion of the vaccination series.
• Any known or suspected allergy to any constituent of influenza vaccines;a history of anaphylactic-type reaction to any constituent of influenza vaccines; or a history of severe adverse reaction to a previous influenza vaccine.
• Known use of an analgesic or antipyretic medication within 12 hours prior to first vaccination.
• Child in Care.