Study of a Combination Vaccine Comprised of Different Recombinant Spike Antigen Levels of a Matrix-M Adjuvanted Recombinant COVID-19 Vaccine and High-Dose Inactivated Influenza Vaccine in Adult Participants 50 Years of Age and Older

Inclusion Criteria:

Inclusion criteria to be checked at Screening Visit

• Aged 50 years or older on the day of inclusion

• Informed consent form has been signed and dated.

• Able to attend all scheduled visits and to comply with all study procedures.

• Participant must be able to receive an injection in the deltoid muscle of both arms.

• Participant must have completed a primary vaccination series against SARS-CoV-2 andat least 1 booster with a locally authorized or approved COVID-19 vaccine.

Inclusion criteria to be checked at Visit 1 (D01):

• Aged 50 years or older on the day of inclusion

• Participants who are healthy or with pre-existing stable condition (defined asdisease not requiring significant change in therapy or hospitalization for worseningdisease during the 12 weeks before enrollment), as determined by medical evaluationincluding medical history and physical examination.

• A female participant is eligible to participate if she is not pregnant orbreastfeeding and one of the following conditions applies:

• Is of non-childbearing potential. To be considered of non-childbearingpotential, a female must be post-menopausal for at least 1 year, or surgicallysterile.

OR

• Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 4 weeks after study intervention administration.

A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) on the day of enrollment before the first dose of study intervention.

• Informed consent form has been signed and dated.

• Able to attend all scheduled visits and to comply with all study procedures.

• Participant must be able to receive an injection in the deltoid muscle of both arms.

• Participant must have completed a primary vaccination series against SARS-CoV-2 andat least 1 booster with a locally authorized or approved COVID-19 vaccine.

Exclusion Criteria:

Exclusion criteria to be checked at Screening Visit and at Visit 1 (D01):

• Known or suspected congenital or acquired immunodeficiency; or receipt ofimmunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy,within the preceding 6 months; or long-term systemic corticosteroid therapy (forglucocorticoids, ≥ 10 milligrams/day of prednisone or equivalent for more than 2consecutive weeks within the past 3 months).

• Known systemic hypersensitivity to any of the study intervention components, orhistory of a life-threatening reaction to the study interventions used in the studyor to a product containing any of the same substances .

• Self-reported thrombocytopenia, contraindicating intramuscular injection, based oninvestigator's judgment.

• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion,contraindicating intramuscular injection, based on investigator's judgment.

• Chronic illness (1) that, in the opinion of the investigator, is at a stage where itmight interfere with study conduct or completion .

• Moderate or severe acute illness/infection (according to investigator judgment) orfebrile illness (temperature ≥ 100.4°F) on the day of study interventionadministration. A prospective participant should not be included in the study untilthe condition has resolved or the febrile event has subsided.

• Alcohol, prescription drug, or substance abuse that, in the opinion of theInvestigator, might interfere with the study conduct or completion.

• History of serious adverse reaction to any influenza or COVID-19 vaccines.

• Personal or family history of Guillain-Barré syndrome.

• Prior history of myocarditis, pericarditis, or myopericarditis.

• Prior history of stroke, transient ischemic attack, or stroke risk factors, whichmay include untreated/uncontrolled hypertension, untreated/uncontrolledhyperlipidemia, active smoking, atrial fibrillation, and additional risk factors,based on investigator's judgment, which may include history of thromboembolicdisease, obesity, cardiac structural or valvular abnormality, carotid stentplacement, or family history of stroke..

• Receipt of any vaccine in the 4 weeks preceding study intervention administration orplanned receipt of any vaccine prior to the second blood draw (ie, approximately inthe 28 days following study intervention administration .

• Previous vaccination against influenza (in the previous 6 months) with aninvestigational or marketed vaccine.

• Previous vaccination against COVID-19 (in the previous 6 months) with aninvestigational or marketed vaccine OR history of COVID-19 in the previous 6 months .

• Receipt of immune globulins, blood or blood-derived products in the past 3 months.

• Participation at the time of study enrollment (or in the 4 weeks preceding studyintervention administration) or planned participation during the present studyperiod in another clinical study investigating a vaccine, drug, medical device, ormedical procedure.

• Deprived of freedom by an administrative or court order, or being in an emergencysetting, or hospitalized involuntarily.

• Identified as an Investigator or employee of the Investigator or study center withdirect involvement in the proposed study, or identified as an immediate familymember (ie, parent, spouse, natural or adopted child) of the Investigator oremployee with direct involvement in the proposed study.

1. Chronic illness may include, but is not limited to, cardiac disorders,hypertension, pulmonary disease, renal disorders, auto-immune disorders,diabetes mellitus, psychiatric disorders, neurologic disorders, or chronicinfection