Immunogenicity and Safety of a Quadrivalent Influenza Vaccine Given by Intramuscular Route in Subjects Aged 18 to 60 Years

Inclusion Criteria: * Aged 18 to 60 years on the day of inclusion * Subjects aged 18 years: Assent form has been signed and dated by the subject or by an independent witness, and informed consent form has been signed and dated by at least one parent or another legally acceptable representative or by an independent witness Subjects aged 19 to 60 years: Informed consent form has been signed and dated by the subject or by an independent witness * Subject and parent/legally acceptable representative (if applicable) are able to attend all scheduled visits and to comply with all trial procedures Exclusion Criteria: * Subject is pregnant, or lactating, or of childbearing potential (to be considered of non-childbearing potential, a female must be pre-menarche or post-menopausal for at least 1 year, surgically sterile, or using an effective method of contraception or abstinence from at least 4 weeks prior to vaccination and until at least 3 weeks after vaccination) * Participation at the time of study enrollment (or in the 4 weeks preceding the trial vaccination) or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure * Receipt of any vaccine in the 4 weeks preceding the trial vaccination or planned receipt of any vaccine until the second visit, 3 weeks following the trial vaccination * Vaccination against influenza if administered in the context of a clinical trial or a flu vaccination campaign or self-reported history of influenza infection (influenza-like illness) in the previous 6 months * Receipt of immune globulins, blood or blood-derived products in the past 3 months * Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months) * Known history of seropositivity for Human Immunodeficiency Virus (HIV) or Hepatitis C * Known systemic hypersensitivity to eggs, chicken proteins, neomycin, formaldehyde and octoxynol-9, or to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the study or to a vaccine containing any of the same substances * Known or suspected thrombocytopenia, contraindicating intramuscular vaccination, based on Investigator's judgment * Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination, based on Investigator's judgment * Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily * Current alcohol abuse or drug addiction * Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion * Moderate or severe acute illness/infection (according to investigator judgment) on the day of vaccination or febrile illness (temperature ≥ 38.0°C). A prospective subject should not be included in the study until the condition has resolved or the febrile event has subsided * Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (i.e., parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study.