The aim of the study was to assess the immunogenicity and safety of Fluzone Quadrivalent influenza vaccine Southern Hemisphere (SH) 2015 formulation in participants aged 18 to 60 years as well as in participants 61 years or older.

The objectives were:

• To evaluate the compliance, in terms of immunogenicity, of the Fluzone Quadrivalent influenza vaccine SH 2015 formulation with the requirements of the European Medicines Agency (EMA) Note for guidance (NfG) CPMP/BWP/214/96
• To describe the immunogenicity of the Fluzone Quadrivalent influenza vaccine SH 2015 formulation
• To describe the safety of the Fluzone Quadrivalent influenza vaccine SH 2015 formulation

All participants received 1 intramuscular dose of Fluzone Quadrivalent vaccine at the first visit.

Immunogenicity and safety were assessed in all participants. Adverse events (AE) defined in EMA NfG CPMP/BWP/214/96 were collected for 3 days after vaccination, solicited AE pre-listed in the diary card were collected for 7 days after vaccination, unsolicited AEs were collected for 21 days after vaccination, and serious adverse event (SAE) information was collected throughout the study.

Inclusion Criteria:

• Participants were >= 18 years of age on the day of inclusion .
• Informed consent form had been signed and dated.
• Able to attend all scheduled visits and to comply with all trial procedures.

Exclusion Criteria:

• History of serious adverse reaction to any influenza vaccine.
• Receipt of any vaccine within 30 days before receiving study vaccine, or plans to receive another vaccine before Visit 2.
• Participation in another interventional clinical trial investigating a vaccine, drug, medical device, or medical procedure in the 30 days preceding the first study vaccination or during the course of the study.
• Self-reported thrombocytopenia, which may be a contraindication for intramuscular vaccination, at the discretion of the Investigator.
• Vaccination against influenza in the previous 12 months if administered in the context of a clinical trial or a flu vaccination campaign.
• Known systemic hypersensitivity to eggs, chicken proteins, or any of the vaccine components, or a history of a life-threatening reaction to the vaccine or to a vaccine containing any of the same substances (the complete list of vaccine components is included in the Prescribing Information) .
• Receipt of immune globulins, blood, or blood-derived products in the past 3 months.
• Bleeding disorder or receipt of anticoagulants in the 3 weeks preceding inclusion, which may be a contraindication for intramuscular vaccination, at the discretion of the Investigator.
• Participant was pregnant, or lactating, or of childbearing potential (to be considered of non-childbearing potential, a female must be 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).
• Any condition that in the opinion of the Investigator would pose a health risk to the participant if enrolled or could interfere with the evaluation of the vaccine.
• Personal history of Guillain-Barré syndrome.
• 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).
• Chronic illness that, in the opinion of the Investigator, is at a stage where it might interfere with trial conduct or completion .
• Known seropositivity for human immunodeficiency virus (HIV), hepatitis B, or hepatitis C, as reported by the participant. (No screening procedures were implemented.)
• Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
• Current alcohol or drug addiction that, in the opinion of the Investigator, might interfere with the ability to comply with trial procedures.
• Moderate or severe acute illness/infection (according to Investigator judgment) or febrile illness (temperature ≥ 38°C) on the day of vaccination. A prospective participant 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 an 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 an Investigator or employee with direct involvement in the proposed study.

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

Analysis was performed using the safety analysis set which included those participants who received at least 1 dose of study vaccine.

AE data were collected from Day 0 (post-vaccination) up to Day 28 post vaccination .

A solicited reaction is an AE that is prelisted in the eCRF and considered to be related to vaccination. A solicited reaction is therefore an adverse drug reaction (ADR) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the eCRF. An unsolicited AE is an observed AE that does not fulfill the conditions prelisted in the eCRF in terms of symptom and/or onset post-vaccination.