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 Japanese Adults 60 Years of Age and Older

Immunogenicity and Safety of High-Dose Quadrivalent Influenza Vaccine (SP0178) Administered by Intramuscular Route Versus Standard-Dose Quadrivalent Influenza Vaccine by Subcutaneous Route in Subjects 60 Years of Age and Older in Japan

Primary Objective:

To demonstrate that QIV-HD induced an immune response (as assessed by hemagglutination inhibition [HAI] geometric mean titers [GMTs] and seroconversion rates) that was superior to responses induced by QIV-SD for the 4 virus strains at 28 days post-vaccination in all participants.

Secondary Objective:

• To describe the immune response induced by QIV-HD and QIV-SD by HAI measurement method in all participants.
• To describe the safety profile of all participants in each study group.

Study duration per participant was approximately 28 days including: 1 day of screening and vaccination, a safety follow-up telephone call and an end of study visit approximately at Day 8 and 28 after vaccination, respectively.

Inclusion criteria :

• Aged greater than or equal to (>=) 60 years on the day of inclusion.
• Able to attend all scheduled visits and complied with all study procedures.

Exclusion criteria:

• Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
• Receipt of any vaccination with live vaccines within the past 27 days preceding the study vaccination or any vaccination with inactivated vaccines within the past 6 days preceding the study vaccination, or planned receipt of any vaccine prior to Visit 02.
• Previous vaccination against influenza (in the preceding 6 months) with either the study 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 eggs, chicken proteins, or any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the study or to a vaccine containing any of the same substances.
• Thrombocytopenia or bleeding disorder, contraindicating IM vaccination based on Investigator's judgment.
• Alcohol or substance abuse that, in the opinion of the Investigator might interfere with the study conduct or completion.
• Chronic illness that, in the opinion of the Investigator, was at a stage where it might interfere with study conduct or completion.
• 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.
• Personal or family history of Guillain-Barré syndrome.
• Neoplastic disease or any hematologic malignancy (except localized skin or prostate cancer that is stable at the time of vaccination in the absence of therapy and participants who have a history of neoplastic disease and have been disease free for >=5 years).
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature >=37.5 degree Celsius). A prospective participant was not be included in the study until the condition had resolved or the febrile event had subsided.
• History of convulsions.
• Any condition that in the opinion of the Investigator could interfere with the evaluation of the vaccine.

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