Evaluate Safety & Immunogenicity of GSK Bio's Influenza Vaccine GSK576389A After Repeated Vaccination in Elderly Adults

Since influenza vaccines are administered every year because of the frequent change in their antigenic composition, the safety and immunogenicity profile of GSK Biologicals' influenza vaccine GSK576389A will be re-evaluated after repeated vaccine administration. In this observer blind study, the subjects previously enrolled in study 104888 (NCT00377585) will receive a dose with the 2007-2008 season's formulations of Fluarix or GSK576389A. Only subjects who were previously enrolled in study 104888 (NCT00377585) are eligible for participation in this study.

This study involves 2 age groups (based on primary study):

Subjects enrolled in the \>= 65 yrs age group in the primary study. Subjects enrolled in the 18-40 yrs age group in the primary study. The study will be conducted in an open manner for this age group.

The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007.

Eligibility Criteria:
Inclusion Criteria:

* Subjects 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.
* Free of an acute aggravation of the health status as established by clinical evaluation before entering into the study.
* If the subject is female, she must be of non-childbearing potential or 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 2 months after completion of the vaccination series.
* Male or female subjects who participated in the 104888 study (NCT00377585) and were enrolled in the \>= 65 years age group or in the 18-40 years age group .

Exclusion Criteria:

* Administration of other licensed vaccines within 2 weeks (for inactivated vaccines) or 4 weeks (for live vaccines) prior to enrolment in this study.
* Planned administration of a vaccine not foreseen by the study protocol up to 30 days after vaccination
* Planned administration of an influenza vaccine other than the study vaccines during the entire study period
* Any vaccination against influenza since January 2007
* Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose.
* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
* History of hypersensitivity to a previous dose of influenza vaccine
* History of allergy or reactions likely to be exacerbated by any component of the vaccine(s)
* Acute (active) clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or pre-existing laboratory screening tests
* Acute disease at the time of enrolment
* Administration of immunoglobulins and/or any blood products within the three months preceding the first dose of study vaccine or planned administration during the study period
* Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days prior to vaccination, or planned use during the study period
* Any medical conditions in which IM injections are contraindicated
* Pregnant or lactating female, or planning to become pregnant or to discontinue contraceptive precautions.