A Study to Assess Immunogenicity Parameters After Vaccination Against Influenza and to Evaluate How These Parameters Change During the Influenza Season

Inclusion Criteria: * Healthy female and male adults aged \>60 years on the day of enrollment * Written informed consent * Females with confirmed menopause (postmenopausal is defined as 12 months with no menses without an alternative medical cause) 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 for season 2011/2012 * 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 the study vaccine, including oral corticosteroids in dosages of ≥0.5 mg/kg/day prednisolone or equivalent (inhaled or topical steroids are allowed) * Known immunodeficiency (including leukemia, HIV seropositivity) or cancer * 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) * Participation in another clinical trial * Employee at the investigational site or relative of the investigator * Anticipated non-compliance with study procedures