This study is to assess whether the Northern Hemisphere 2009/2010 season influenza vaccine Inflexal V fulfills the EMEA requirements for re-registration of influenza vaccines.

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

Safety assessments were made by the investigator at baseline and on Day 22 (± 2 days), and by subjects themselves (Subject Diary) for the 4-day period post-vaccination. SAE surveillance extended to 6 months post-vaccination.