No comparator is administered, only one IM single dose of trivalent subunit inactivated influenza vaccine is administered during the vaccination visit

This phase II is performed as a multicenter study in adult and elderly subjects. Enrolled subjects received one single IM dose of trivalent subunit inactivated flu vaccine during the vaccination visit, according to the study protocol (follow-up period: until day 22) .

To evaluate the antibody response to each influenza vaccine antigen, as measured by Single Radial Hemolysis (SRH) and/or HI at 21 days post-immunization in compliance with the requirements of the current EU recommendations for clinical trials related to yearly licensing of influenza vaccines.