The primary objective of this study is to describe the safety of the Quadrivalent Influenza Vaccine (QIV). Safety is assessed throughout the study period, and includes solicited injection site and systemic reactions (Day 0 to Day 7 post-vaccination); unsolicited adverse events up to Day 28, and serious adverse events occurring throughout the study.

Study duration for previously unvaccinated participants aged 6 months to 8 years is approximately 56 days. Study duration for previously vaccinated participants aged 6 months to 8 years and any participant aged 9 years and older is approximately 28 days.

Inclusion criteria :

• Aged 6 months and older on the day of inclusion
• Participants aged < 18 years: ICF has been signed and dated by the parent or another legally acceptable representative; Assent form has been signed and dated by the participant aged 12 to 15 years.
• Participants aged ≥ 16 years: ICF signed and dated by the participant.
• Participants are able to attend all scheduled visits and to comply with all study procedures. For participants aged 6 months to 17 years, parent/legally acceptable representative are able to attend all scheduled visits and to comply with all study procedures
• For participants < 2 years: Born at full term of pregnancy (≥ 37 weeks) and/or with a birth weight ≥ 2.5 kg

Exclusion criteria:

• Participant is pregnant, or lactating, or of childbearing potential and not using 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 woman must be pre-menarche or post-menopausal for at least 1 year, or surgically sterile
• Participation at the time of study enrollment (or in the 4 weeks preceding study vaccination) or planned participation during the present study period in another clinical study investigating a vaccine, drug, device, or medical procedure
• Receipt of any vaccine in the 4 weeks preceding the study vaccination or planned receipt of any vaccine in the 4 weeks following the study vaccination.
• 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 vaccine used in the study or to a vaccine containing any of the same substances
• Known thrombocytopenia, contraindicating intramuscular vaccination based on investigator's judgment
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM 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 study conduct or completion
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness/body temperature (temperature ≥ 37.5 C or ≤ 35.5 C). A prospective subject should not be included in the study until the condition has resolved or the febrile event has subsided
• Identified as 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

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

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org