Study to Assess the Immune Response and the Safety Profile of a High-Dose Quadrivalent Influenza Vaccine (QIV-HD) Compared to a Standard-Dose Quadrivalent Influenza Vaccine (QIV-SD) in Europeans Adults 60 Years of Age and Older

Immunogenicity and Safety of a High-Dose Quadrivalent Influenza Vaccine Administered by the Intramuscular Route in Subjects 60 Years of Age and Older

Primary Objective:

To demonstrate that high-dose quadrivalent influenza vaccine (QIV-HD) induces an immune response that is superior to the responses induced by standard-dose quadrivalent influenza vaccine (QIV-SD) for all 4 virus strains 28 days post-vaccination in participants 60 to 64 years of age and in participants 65 years of age and older.

Secondary Objective:

• Immunogenicity: To further describe the immune response induced by QIV-HD and QIV-SD in all participants by age group, in pooled age groups, and by vaccine group (QIV-HD; QIV-SD).
• Safety: To describe the safety profile of all participants by age group, in pooled age groups, and by vaccine group (QIV-HD; QIV-SD).

Study duration per participant was approximately 6 months including: 1 day of screening and vaccination, an end of study visit and safety follow-up telephone call approximately at Day 28 and Day 180 after vaccination, respectively.

Inclusion criteria :

• Sixty years of age and older on the day of inclusion.
• Able to attend all scheduled visits and complied with all trial procedures.

Exclusion criteria:

• Participant was pregnant, or lactating, or of childbearing potential and did not used an effective method of contraception or abstinence from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination. To be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year, or surgically sterile.
• Participation at the time of study enrollment (or in the 4 weeks [28 days] 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 (28 days) preceding the trial vaccination or planned receipt of any vaccine prior to Visit 02.
• Previous vaccination against influenza (in the previous 6 months) with either the trial vaccine or another vaccine.
• 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 systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the trial or to a vaccine containing any of the same substances.
• Thrombocytopenia or bleeding disorder, contraindicating IM vaccination based on Investigator's judgement.
• Alcohol or substance abuse that, in the opinion of the Investigator might interfere with the trial conduct or completion.
• 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) or febrile illness (temperature greater than or equal to (>=) 38.0 degree Celsius) on the day of vaccination. A prospective participant should not be included in the study until the condition had resolved or the febrile event had 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 (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study.
• Personal or family history of Guillain Barré syndrome.
• Neoplastic disease or any hematologic malignancy (except localized skin or prostate cancer that was stable at the time of vaccination in the absence of therapy and participants who had a history of neoplastic disease and had been disease free for >= 5 years)

The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.