Efficacy Study of Two Influenza Vaccines and Placebo in Healthy Adult Subjects

Inclusion Criteria: 1. subjects 18 to 49 years of age; 2. in good health as determined by medical history and physical examination; 3. able and willing to provide written informed consent prior to any study procedure; 4. able to comply with all study procedures, including availability and willingness to be actively followed throughout the ensuing influenza season with weekly telephone calls and to comply with the need for prompt collection of nasal and throat specimens in the event of influenza symptoms. Exclusion Criteria: 1. history of anaphylaxis or serious reaction after administration of any vaccine, or hypersensitivity to eggs, egg protein, chicken feathers, influenza viral protein, neomycin, kanamycin, or any other vaccine component, chemically related substance, or component of the potential packaging materials; 2. any health condition for which the inactivated vaccine is recommended by the Advisory Committee on Immunization Practices (ACIP) including chronic diseases of the pulmonary or cardiovascular systems (including asthma), chronic metabolic diseases (including diabetes), renal dysfunction, hemoglobinopathies, immune deficiency disease (including HIV infection) or on-going immunosuppressive therapy; 3. employment in professions prone to influenza transmission to or from high-risk populations (this exclusion specifically includes nurses, physicians, all other healthcare workers with direct patient contact; and police, fire, and rescue personnel); or living in the same household as an immunocompromised person; 4. history of Guillain-Barré syndrome; 5. bleeding diathesis; 6. receipt of another investigational agent within 90 days prior to enrollment in the study or before completion of the safety follow-up period in another study, whichever is longer, and unwilling to refuse participation in another clinical study through the end of the study; 7. receipt of another vaccine within 2 weeks (for inactivated vaccines) or 4 weeks (for live vaccines) prior to Visit 1; 8. laboratory-confirmed influenza disease within 6 months prior to Visit 1; 9. receipt of an influenza vaccine within 6 months prior to Visit 1 or plans to receive influenza vaccine outside of this study; 10. experienced a temperature (≥100.0°F / ≥37.8°C) and/or any acute illness within 3 days prior to study vaccination; 11. pregnant or breast-feeding female; 12. if female of childbearing potential and sexually active, has not used any of the birth control methods detailed in the section entitled "Females of Childbearing Potential" for at least 2 months prior to study entry; 13. if female of childbearing potential and sexually active, refusal to use a reliable contraceptive method as detailed in the section entitled "Females of Childbearing Potential" during the first 3 weeks after vaccination; 14. research staff directly involved with the clinical study or family members or household members of research staff. Research staff are individuals with direct or indirect contact with study subjects, or study site personnel who have access to any study documents containing subject information. This would include receptionists, persons scheduling appointments or making screening calls, regulatory specialists, laboratory technicians, etc.; 15. any condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives or with the safety of the study subject.