Immunogenicity, Safety and Tolerability of a Trivalent Subunit Inactivated Vaccine in Healthy Subjects 50 Years and Above

Inclusion Criteria: * Males and females aged 50 years and above, mentally competent, willing and able to give written informed consent prior to study entry and after the nature of the study has been explained according to local regulatory requirements. * Individuals able to comply with all the study requirements. * Individuals in good health as determined by the outcome of medical history, physical examination and clinical judgment of the investigator. Exclusion Criteria: * Individuals with behavioral or cognitive impairment or psychiatric disease that, in the opinion of the investigator, may interfere with the subject's ability to participate in the study. * Individuals with any progressive or severe neurologic disorder, seizure disorder or Guillain-Barré syndrome. * Individuals who are not able to comprehend and to follow all required study procedures for the whole period of the study. * Individuals who have received any seasonal or pandemic influenza vaccine or have had a laboratory confirmed seasonal or pandemic influenza disease within the past 6 months. * Individuals with history or any illness that, in the opinion of the investigator, might interfere with the results of the study or pose additional risk to the subjects due to participation in the study. * Individuals with positive HIV test result, with history of an autoimmune disorder or any other known or suspected impairment /alteration of the immune system, or under immunosuppressive therapy within 6 months or use of any parenteral or oral corticosteroids within the previous 30 days. * Individuals with a known bleeding diathesis, or any condition that may be associated with a prolonged bleeding time. * Individuals with any serious chronic or progressive disease according to judgment of the investigator (neoplasm, insulin dependent diabetes, cardiac, renal or hepatic disease). * Individuals who have any malignancy (excluding nonmelanotic skin cancer) or lymphoproliferative disorder. * Individuals with history of any anaphylactic adverse event and/or serious allergic adverse event following a vaccination, a proven hypersensitivity to any component of the study vaccine (eg, to eggs or eggs product as well as ovalbumin, chicken protein, chicken feathers, influenza viral protein, kanamycin and neomycin sulphate) or latex allergy. * Individuals participating in any clinical trial with another investigational product 30 days prior to first study visit or intent to participate in another clinical study at any time during the conduct of this study. * Receipt of nonstudy vaccines (with the exception of post-exposure vaccination in a medical emergency, eg, hepatitis, rabies, tetanus) within 3 weeks prior to Visit 1. * Individuals who have ever received blood, blood products and/or plasma derivatives or any parenteral immunoglobulin preparation in the past 12 weeks. * Individuals who have received antibiotics within 6 days before vaccination. * Individuals with body temperature (axillary temperature) ≥38 degrees Celsius (≥ 100.4° F) within the last 3 days of intended study vaccination. * BMI \> 35 kg/m2. * Female who are pregnant or nursing (breastfeeding) mothers or females of childbearing potential do not plan to use acceptable birth control measures, for the whole duration of the study. Adequate contraception is defined as hormonal (eg, oral, injection, transdermal patch, implant, cervical ring), barrier (eg, condom with spermicide or diaphragm with spermicide), intrauterine device (IUD), or monogamous relationship with vasectomized partner who has been vasectomized for 6 months or more prior to the subject's study entry; Abstinence. * Individuals who are part of study personnel or close family members conducting this study. * Individuals with history of substance or alcohol abuse within the past 2 years.