Safety of and Immune Response to a Bird Flu Virus Vaccine (H9N2) in Healthy Adults (Study A)

Avian influenza (AI), or bird flu, has recently become a major health concern in Asia and other parts of the world. The purpose of this study is to test the safety of and immune response to a new AI vaccine in healthy adults. Study hypothesis: Influenza A viruses are widely distributed in nature and infect a wide variety of birds and mammals. The direct transmission of avian influenza viruses from birds to humans has recently become a major health concern in Asia and other parts of the world, raising concern of a possible influenza pandemic in humans. This vaccine will evaluate the safety, infectivity and immunogenicity of Live Influenza A vaccine H9N2 (6-2) AA ca reassortant (A/chicken/Hong Kong/G9/97 x A/Ann Arbor/6/60 ca), a cold-adapted, live attenuated virus vaccine administered intranasally for the protection of humans against pandemic influenza viruses of the H9N2 subtype.