A Study to Learn About a Combined COVID-19 and Influenza Shot in Healthy Adults

The purpose of this clinical trial is to see if combining a licensed COVID-19 vaccine and a licensed influenza vaccine into a single shot is safe and can help produce antibodies to defend the body against both SARS-CoV-2 (the virus that causes COVID-19) and influenza. Participants enrolled in this trial will be healthy adults, 50 years of age or older.

This is a Phase 1/2 study to evaluate the safety, tolerability, and immunogenicity of licensed BNT162b2 (Omi XBB.1.5) and recombinant influenza vaccine (RIV) administered together as a single injection (referred to as BNT162b2 \[Omi XBB.1.5\]/RIV) in healthy adults 50 years of age or older.

The safety, tolerability, and immunogenicity of BNT162b2 (OmiXBB1.5)/RIV administered as a single injection will be compared to BNT162b2 (Omi XBB.1.5) and RIV administered simultaneously as 2 separate injections (coadministered), and to BNT162b2 (Omi XBB.1.5) or RIV when administered alone.

Across Phases 1 and 2, approximately 640 participants in total will be randomized with an equal randomization ratio to 1 of 4 vaccine groups and stratified by age.

Eligibility Criteria:
Inclusion Criteria:

* Male or female participants aged 50 years or older at Visit 1 (Day 1).
* Participants who are willing and able to comply with all scheduled visits, the investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
* Healthy participants who are determined by medical history, physical examination (if required), and clinical judgment of the investigator to be eligible for inclusion in the study.
* Capable of giving signed informed consent as described in the protocol, which includes compliance with the requirements and restrictions listed in the informed consent document (ICD) and in the protocol.

Exclusion Criteria:

* Any medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
* Known infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV).
* History of severe adverse reaction associated with any vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study interventions.
* Participants with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic or cutaneous lupus erythematosus, autoimmune arthritis/rheumatoid arthritis, multiple sclerosis, Sjögren's syndrome, idiopathic thrombocytopenia purpura, glomerulonephritis, autoimmune thyroiditis, temporal arteritis, psoriasis, and/or insulin-dependent diabetes mellitus.
* Immunocompromised individuals with known or suspected immunodeficiency, determined by history and/or laboratory/physical examination.
* Current heart disease, uncontrolled hypertension, or a prior history of myocarditis or pericarditis.
* Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.
* Women who are pregnant, plan to become pregnant during the study, or are breastfeeding.
* Prior history of ischemic stroke or transient ischemic attack.
* Prior history of Guillain-Barré syndrome (GBS).
* Participants with a calculated BMI of ≥35.
* Receipt of chronic medications with known systemic immunosuppressant effects (including cytotoxic agents or systemic corticosteroids), or radiotherapy, within 60 days before enrollment through conclusion of the study.
* Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies used for the treatment or prevention of COVID 19 or those that are considered immunosuppressive, from 90 days before study intervention administration, or planned receipt throughout the study.
* Vaccination with any investigational or licensed influenza vaccine within 6 months (180 days) before study intervention administration, or ongoing receipt of chronic antiviral therapy with activity against influenza.
* Vaccination with any investigational or licensed COVID-19 vaccine within 6 months (180 days) before study intervention administration.
* Participation in other studies involving administration of an investigational product within 28 days prior to, and/or during, participation in this study.
* Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.
* Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
* Current alcohol abuse or drug addiction that in the opinion of the investigator might interfere with the study conduct or completion.