A Randomized, Double-blind, Placebo-controlled, Post-marketing Phase III Study to Evaluate the Efficacy of GSK Biologicals' Influenza Vaccine (Fluarix™) Administered Intramuscularly in Adults.

As a result of the recent supply shortages in the U.S., as well as an anticipated increase in demand during the coming years, GSK Biologicals is pursuing licensure of Fluarix in the U.S. under the accelerated approval process; marketing approval most likely will be granted before the start of this clinical trial. GSK proposes to support U.S. licensure of Fluarix with this confirmatory post-marketing study. The purpose of the study is to evaluate the efficacy of a single dose of Fluarix in preventing influenza in adults during the 2005/2006 Influenza season.