A Re-licensing Study to Assess the Efficacy of Inflexal V Formulated With WHO Recommended 2009/2010 Influenza Virus Strains for the Northern Hemisphere

Inclusion Criteria: * Healthy female and male adults * Aged ≥18 to ≤60 years or \>60 years on Day 1 * Written informed consent Exclusion criteria: * Acute exacerbation of bronchopulmonary infection (cough, sputum, lung findings) or other acute disease * Acute febrile illness (≥38.0 °C) * Prior vaccination with an influenza vaccine in the past 330 days * Known hypersensitivity to any vaccine component * Previous history of a serious adverse reaction to influenza vaccine * History of egg protein allergy or severe atopy * Known blood coagulation disorder * Chronic (longer than 14 days) administration of immunosuppressants or other immune-modifying drugs within 6 months before the first dose of study vaccine, incl. oral corticosteroids in dosages of ≥0.5 mg/kg/d prednisolone or equivalent (inhaled or topical steroids are allowed) * Known immunodeficiency (incl. leukemia, cancer, HIV seropositivity) * Investigational medicinal product received in the past 3 months (90 days) * Treatment with immunoglobulins or blood transfusion(s) received in the past 3 months (90 days) * Pregnancy or lactation * Participation in another clinical trial * Employee at the investigational site, or relative or spouse of the investigator * Suspected non-compliance