H5N1 Priming and Boosting Strategies

Severe disease in humans due to bird influenza viruses (H5N1) has led to concern that this virus may result in a widespread outbreak of bird flu. The purpose of this study is to evaluate the dose and dosing schedule for 2 different types of H5N1 vaccine. Participants will be randomly assigned to 1 of 9 possible vaccine groups. All participants will receive 2 doses of Clade 1, Clade 2, or combination Clade 1 and 2 on Day 0. All participants will receive a second dose of the same vaccine or a different vaccine type on study day 7, 14, 28 or 180. Study participants will include about 500 healthy adult subjects, ages 18-49 years old, who have no history of prior H5 flu exposure or vaccination. Study procedures may include medical history, physical exam, and blood sampling. Subject participation may last up to 372 days. Several DMID studies have recently evaluated H5N1 vaccines in healthy adults, 04-063, 05-0090, 05-0015, and 05-0043.