The present phase III study aims to evaluate the safety and immunogenicity of the MF59-adjuvanted subunit seasonal influenza vaccine and to evaluate the consistency in the manufacturing process of three consecutive lots of MF59-adjuvanted subunit seasonal influenza vaccine with respect to immunogenicity in subjects aged 65 years and older.

The active comparator non-adjuvanted seasonal influenza vaccine is approved for use in this age group in the United States and will be used to provide a comparative assessment for immunogenicity and safety.