Post-marketing Study to Evaluate the Efficacy of Influenza Vaccine

Inclusion Criteria: * A male or female age between, and including, 18 and 64 years of age at the time of the vaccination. * Written informed consent obtained from the subject. * Availability to follow up by phone during the study period. * Female subjects must be of non-childbearing potential, i.e. either surgically sterilized or one year post-menopausal. If subject is of childbearing potential, she must be abstinent or have used adequate contraceptive precautions for 30 days prior to vaccination. She must also have a negative pregnancy test at study entry and must agree to continue such precautions for two months after vaccination. Exclusion Criteria: * History of hypersensitivity to a previous dose of influenza vaccine. * History of allergy or reactions likely to be exacerbated by any component of the vaccine including egg, chicken protein, formaldehyde, thimerosal, gentamicin sulfate or sodium deoxycholate. * Acute disease at the time of enrollment. (Acute disease is defined as the presence of a moderate or severe illness with or without fever). All vaccines can be administered to persons with a minor illness such as diarrhea, mild upper respiratory infection with or without low-grade febrile illness, i.e. Oral temperature \< 37.5°C). * Pregnancy * Chronic disorders of the pulmonary or cardiovascular system, including asthma * History of requiring regular medical follow-up or hospitalization during the preceding year because of chronic metabolic diseases (including diabetes mellitus), renal dysfunction, hemoglobinopathies, or immunosuppression (including immunosuppression caused by medications or by human immunodeficiency virus.