Immunogenicity and Safety Study to Evaluate Different Formulations of GSK Biologicals' Influenza Vaccine GSK576389A

Inclusion Criteria

• Subjects who the investigator believes that they can and will comply with the requirements of the protocol should be enrolled in the study.
• A male or female aged 18-40 years old or 65 years or older at the time of the vaccination.
• Written informed consent obtained from the subject.
• Free of an acute aggravation of the health status as established by clinical evaluation (medical history and medical history directed examination) 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.

Exclusion Criteria

• 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.
• 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 during the entire study period.
• Planned administration of an influenza vaccine other than the study vaccines during the entire study period.
• Vaccination against influenza since January 2007 (with 2007/2008 or 2006/2007 influenza vaccine).
• Administration of more than 14 days of immunosuppressants or other immune-modifying drugs within 6 months prior to the administration of the study vaccine.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination
• Hypersensitivity to a previous dose of influenza vaccine.
• Allergy to any component of the vaccine.
• Acute (active) clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality.
• Acute disease at the time of enrolment. (Acute disease is defined as the presence of a moderate or severe illness with or without fever. All vaccines can be administered to persons with a minor illness such as diarrhoea, mild upper respiratory infection with or without low-grade febrile illness, i.e. axillary temperature<37.5ºC (99.5ºF).
• Administration of immunoglobulins and/or any blood products within the three months preceding the first administration of the study vaccine or planned administration during the study.
• Any medical conditions in which IM injections are contraindicated.
• Lactating female or female planning to become pregnant or to discontinue contraceptive precautions