Clinical Study in Children, 6 Months to 3 Years of Age, to Assess Two Dose Levels of an Experimental Flu Vaccine, Using a Licensed Influenza Virus Vaccine, Vaxigrip® as the Control

Children younger than 5 years of age are at high risk for severe influenza disease (flu) and hospitalization due to flu. Scientists are in the process of re-evaluating the dosing initially based on whole virus vaccines to improve their efficacy in infants. In this study, we will compare two different dose levels of GSK1557482A flu vaccine. Another already approved flu vaccine made by a different company will be used as a control.

This is a study of two different dose levels of a new formulation of flu vaccine for the 2008/2009 flu season using the World Health Organization recommended virus strains. Subjects will be randomly put into one of three different groups to receive either one or two doses of:

0.25 mL dose of the new flu vaccine, or 0.5 mL dose of the new flu vaccine or the licensed Vaxigrip flu vaccine (control) The parents of the subjects and the study doctor and nurses will not know the group of their child until the study is completed.

The children will be vaccinated with either one dose or two doses depending on whether or not they have received a flu vaccine before. The doctor will decide on the schedule for each child based on the information provided by the parents. The active phase of the study will last approximately two months for children receiving two doses and one month for those receiving a single dose. An extended safety follow-up will continue until Study Month 6.

Two blood samples will be taken from each subject. These will be used to evaluate how well the vaccine works in the children and which dose level works best compared to the control.

The parents will fill in a diary card for four days to record any reactions or symptoms which may occur after vaccination. Parents will also keep a record of other symptoms that may occur between vaccinations and up to six months after the first vaccination and will keep a record of any medication their child takes in this time period.

Eligibility Criteria:
Inclusion Criteria:

* A male or female child 6 months to \< 3 years of age at the time of the vaccination, regardless of previous administration of influenza vaccine in a previous season;
* Subjects must be in good health established by medical history and physical examination before entering into the study;
* Subjects having a parent/guardian who the investigator believes can and will comply with the requirements of the protocol should be enrolled in the study;
* Written informed consent obtained from the subject's parent/guardian.
* Parents/guardian access to a consistent means of telephone contact, land line or mobile

Exclusion Criteria:

* Use of any investigational or non-registered product (drug or vaccine) within 30 days preceding the administration of the study vaccine or planned use during the study period. Routine, registered childhood vaccinations are not an exclusion criterion;
* History of hypersensitivity to any vaccine;
* History of allergy to or reactions likely to be exacerbated by, any component of the vaccine including egg, chicken protein, formaldehyde, or sodium deoxycholate;
* History of any congenital, acquired, or iatrogenic immunodeficiency state (current or potential) including HIV infection, disorders of the lymphoid system or bone marrow, or chronic administration (defined as more than 14 consecutive days) of immunosuppressant or other immune-modifying drugs within 3 months prior to the administration of the study vaccine.
* Acute disease at the time of enrolment.
* History of Guillain Barré syndrome within 6 weeks of receipt of prior inactivated influenza virus vaccine;
* Any significant disorder of blood coagulation or treatment with vitamin K antagonists; or any known disorder of hemostasis;
* Receipt of any immunoglobulins and/or any blood products within three months of study enrollment or planned administration of any of these products during the study period.
* Receipt of a non-study related influenza vaccine outside of this study and during the current (2008-09) influenza immunization campaign.
* Any use of analgesics/antipyretics 12 hours before receipt of vaccine.