Influenza (flu) viruses change continuously, therefore also the parts of viruses used in influenza vaccines can vary from year to year. In Europe, manufacturers/marketing holders of these vaccines are required to be involved in ongoing clinical trials and to present the results to the competent authorities each year. The current study is a phase IIIa clinical trial with a commercially available vaccine (Influvac®) supplied in pre filled syringes. It is part of the ongoing clinical trial program for Influvac® and will be done to assess the immunogenicity and safety and tolerability of next season's trivalent influenza subunit vaccine in two groups of healthy subjects: subjects aged >= 18 and <= 60 years and subjects >= 61 years of age (elderly).

Inclusion Criteria:

• Willing and able to give informed consent and able to adhere to all protocol required study procedures.
• Men and women aged ≥ 18 and ≤ 60 years or ≥ 61 years of age at the day of study vaccination.
• Being in good health as judged by medical history, physical examination and clinical judgment of the investigator.

Exclusion Criteria:

• Known to be allergic to eggs, chicken protein, gentamicin or any other constituent of the vaccine.
• A serious adverse reaction after a previous (influenza) vaccination. Presence of any significant condition that may prohibit inclusion as determined by the investigator.
• Having received vaccination against influenza within the previous six months before study vaccination or planned vaccination during the study period.
• A history of Guillain-Barré syndrome or active neurological disease.