A Study to Find the Dose and Assess the Immune Response and Safety of a Vaccine Against Influenza in Healthy Younger and Older Adults

Exclusion criteria

• . Participant tested positive for influenza by local health authority-approved testing methods within 180 days prior to Day 1.
• . Current or past malignancy, unless completely resolved without sequelae for greater than (\>) 5 years before the study intervention administration (excluding effectively treated basal cell skin cancer).
• . Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination (no laboratory testing required). HIV-infected individuals may be enrolled if they have been stable on antiretroviral therapy for the past 6 consecutive months, i.e., their treatment has not been modified, their cluster of differentiation 4 (CD4) cell count is \>= 200/ cubic millimeter (mm³) and their viral load has been undetectable (i.e., HIV-RNA lesser than (\<) 50 copies/milliliter \[mL\]) (based on medical records, no laboratory testing required).
• . Participants with a history of, or current suspicion of myocarditis, pericarditis, or idiopathic cardiomyopathy (including a history of myocarditis or pericarditis following vaccination with an mRNA COVID-19 vaccine), or presence of any medical condition that increases risk of myocarditis or pericarditis, including cocaine abuse, cardiomyopathy, endomyocardial fibrosis, hypereosinophilic syndrome, hypersensitivity myocarditis, eosinophilic granulomatosis with polyangiitis and persistent myocardial infection will be excluded from the study.
• . History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention (including polyethylene glycol, egg proteins and aminoglycoside antibiotics).
• . Hypersensitivity to latex.
• . Recurrent history or uncontrolled neurological disorders or seizures, including Guillain-Barré syndrome and Bell's palsy, with the exception of febrile seizures during childhood.
• . Any history of dementia or any medical condition that moderately or severely impairs cognition.

Part 2 OA: GMI of Antigen 1 Antibody Titers

Timeframe: From Day 1 (baseline) to Day 29