Inactivated Influenza A/H5N1 Vaccine in the Elderly

The purpose of this research study is to compare how the body reacts to different strengths of a new H5N1 flu vaccine. Researchers will also look at how antibodies are made after subjects receive the H5N1 flu vaccine. Participants will include at least 240 healthy males and females, aged 65 and older. The vaccine is given as an injection or shot in the arm. Subjects will receive 3 doses of vaccine at Day 0, Month 1 and Month 6. There are 2 different doses of the new H5N1 vaccine that will be given in this study. There is also a chance that a subject may receive a placebo (dummy) injection of saltwater instead of the flu vaccine. Study procedures will include physical exams and blood sample collections. Additionally, participants will complete a memory aid card to document daily temperatures and any symptoms experienced for a week after receiving vaccine. The length of participation in this study will be approximately 14 months.