 This Phase 3 study evaluates the safety, immunogenicity and lot-to lot consistency of 3 lots of aH5N1c vaccine for pandemic avian influenza, in approximately 2394 healthy adults 18 years of age receiving the vaccine and 798 healthy adults receiving placebo. Subjects will be randomized in a 3:1 ratio to receive either aH5N1c vaccine or saline placebo. Enrollment will be stratified by age: 18 to 65 years of age and 65 years of age, to allow adequate safety assessment of the entire age spectrum. 