Since influenza vaccines are normally administered every year because of the frequent change in their antigenic composition, the safety and immunogenicity profiles of the adjuvanted influenza vaccine need to be re-evaluated after repeated vaccine administration. In this study, subjects enrolled in a previous study will receive a booster dose with the 2006-2007 season's formulations of Fluarix or the adjuvanted vaccine.

Inclusion Criteria:

• The subjects must be healthy adults ages 18-40 years or >/= 65 years previously vaccinated with either Fluarix or the adjuvanted vaccine.

Exclusion Criteria:

• Subjects will be excluded if they take/have taken chronically high doses of immunosuppressants or other immune modifying drugs within six months before vaccination, or immunoglobulins or blood products within three months before vaccination, or any investigational product within 30 days before vaccination
• Have a history of influenza infection since previous vaccination
• Women who are pregnant
• Subjects who have an acute or chronic clinically significant disease or an immunosuppressive/deficient condition, or have contra-indications to influenza vaccination

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