Sanofi H1N1 Influenza Vaccine Administered at Different Dose Levels With and Without AS03 Adjuvant in Healthy Adult and Elderly Populations

The purpose of this study is to see how the body reacts to different strengths of the H1N1 flu shot when it is given with or without an "adjuvant." An adjuvant is a substance that may cause the body to produce more antibodies when it is given with a vaccine. This study will also compare how age affects the body's response to the H1N1 flu shot. In this study, 3 strengths of the H1N1 flu shot will be tested combined with an adjuvant. In addition, 2 strengths of the H1N1 flu shot will be tested without adjuvant. Two H1N1 flu shots of the same strength, with or without adjuvant, will be given about 3 weeks apart. Participants will include up to 800 healthy adults, approximately 500 individuals ages 18-64 and 250 individuals greater than or equal to age 65. Study procedures include: physical exam, blood samples, completing a memory aid to record vaccine side effects, medications and daily oral temperature. Participants will be involved in study related procedures for up to 13 months.