Safety Study of an Adjuvanted Candidate Influenza Vaccine to Prevent Influenza Disease in the Elderly Population

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.