Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccine MRT5413 in Adult Participants18 Years of Age and Older

The purpose of this study is to evaluate the safety and immunogenicity of a single intramuscular (IM) injection of up to 3 dose levels of Quadrivalent Influenza messenger ribonucleic acid (mRNA) Vaccine MRT5413 compared to an active control (QIVstandard-dose (SD), QIV high-dose (HD) [adults ≥ 65 years of age only], or quadrivalent recombinant influenza vaccine (RIV4)) in adults 18 years of age and older.

Inclusion Criteria:Aged 18 years on the day of inclusion (US) and aged 21 years on the day of inclusion (Puerto Rico)A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year, or surgically sterile ORIs 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 12 weeks after study intervention administration.Exclusion Criteria:Participants are excluded from the study if any of the following criteria apply: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)Previous history of myocarditis, pericarditis, and / or myopericarditisSelf-reported thrombocytopenia, contraindicating Intramuscular vaccination based on Investigator's judgmentBleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating Intramuscular vaccination based on Investigator's judgmentModerate or severe acute illness / infection (according to Investigator's judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) 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 subsidedSelf-reported or documented seropositivity for human immunodeficiency virus, hepatitis B virus, or hepatitis C virusNOTE: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.