Trivalent rHA Dose Escalation Study in Elderly Subjects

Approximately 400 healthy, ambulatory adults ages 65-80 will be randomized into one of four study groups to receive a single immunization of a licensed trivalent inactivated influenza vaccine or one of three dose levels of an investigatioanl trivalent recombinant influenza HA protein vaccine. The study will be conducted in 2 stages. In the first stage, 80 subjects will be randomized (20 per group) and receive one vaccination on Day 0. Safety will be evaluated after Stage 1 subjects have completed a 7 day follow-up. Enrollment of Stage 2 subjects will begin after the safety data for Stage 1 has been reviewed. In Stage 2, 320 subjects will be randomized (80 per group) and receive one vaccination on Day 0. Blood and nasal secretions will be collected prior to an approximately one month after vaccination to assess antibody responses.