AI is caused by a virus that occurs naturally among birds. Because the virus has the ability to mutate into a form that can efficiently spread among the human population, AI has the potential to cause pandemics. The purpose of this study is to evaluate the safety of and immune response to the AI vaccine H9N2 (6-2) AA ca Reassortant (A/Chicken/Hong Kong/G9/97 x A/Ann Arbor/6/60 ca) in healthy adults who have never been exposed to the H9N2 virus.