The purpose of this study is to compare the body's reactions and immune responses after receiving different strengths of a H9N2 influenza virus vaccine with and without an adjuvant given into the arm muscle. Study participants will include up to 96 healthy adults, ages 18-34. The 4 dosages of the experimental H9N2 vaccine to be tested in this study are the following: 3.75, 7.5, 15, and 30-mcg (with and without MF59 adjuvant). Participants will be vaccinated on Days 0 and 28. Participants will record any vaccine side effects in a diary for 7 days following each vaccination. Participants will return to the clinic on days 2 and 7 after vaccination. Blood samples will be collected 7 days following each vaccination. Serum and nasal wash specimens will be collected before each vaccination and 4 weeks after injections (0, 4, and 8 weeks). Participants will be involved in study related procedures for up to 8 months.