As influenza vaccine efficacy is reported to be lower in elderly subjects compared to healthy adults, probably as a result of immunosenescence, there is a desire to devise ways to increase the current vaccines efficacy for this target population. Adjuvants are known to boost immune responses, thus representing one way to increase the efficacy of the current GlaxoSmithKline Fluarix™ influenza vaccine in elderly subjects. The purpose of this study is to evaluate the immunogenicity and the reactogenicity of a revaccination with the adjuvanted GlaxoSmithKline influenza vaccine administered intramuscularly about 1 year after administration of the first dose of vaccine. For immunogenicity and safety evaluations, subjects who have already received Fluarix™ during the preceeding year will receive a dose of commercial vaccine and will form the control group of this trial.

Inclusion Criteria:

• A male or female aged over 65 years at the time of the revaccination; who previously received the adjuvanted candidate vaccine or Fluarix during a clinical study organized during the preceeding year

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the administration of the study vaccine, or planned use during the study period.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the administration of the study vaccine.
• History of confirmed influenza infection since a year from the date of previous vaccination.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination
• History of hypersensitivity to vaccines.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• Acute clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Acute disease at the time of enrolment.
• Administration of immunoglobulins and/or any blood products within the three months preceding the administration of the study vaccine or during the study.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.