Immunogenicity & Safety of GSK's Avian Flu Vaccine 1557484A Given to Adults Aged ≥18 Years

All subjects will receive 3 doses of study vaccine, including 2 doses of active vaccine and 1 dose of placebo. All subjects will attend formal study center visits for safety and immunogenicity assessments on Days 0, 10, 42, 182, 192, 224, 549, 559, 591, and 729. A telephone contact to assess safety will be made at Day 364 and Day 909.