A Study of mRNA-1018-H5 Pandemic Influenza Vaccine in Healthy Adults

Key Inclusion Criteria: * Healthy as determined by medical evaluation including medical history; and physical examination. Participants with clinically stable chronic medical conditions are permitted. * Participants who are assigned female at birth or could become pregnant are eligible to participate if the participant is not pregnant or breast/chest feeding, and one of the following conditions applies: * Is a person of nonchildbearing potential (PONCBP) OR * Is a person of childbearing potential (POCBP) * A POCBP must have a negative highly sensitive pregnancy test at Screening and on the day of the first dose of study intervention. Key Exclusion Criteria: * Participant is acutely ill or febrile (body temperature ≥ 38.0 degrees Celsius \[°C\]/100.4 degrees Fahrenheit \[°F\]) within 72 hours prior to or at the Screening Visit or Day 1. * History of myocarditis, pericarditis, or myopericarditis. * History of Guillain-Barre syndrome. * Reported history of congenital or acquired immunodeficiency, immunosuppressive condition, asplenia, or recurrent severe infections disease. * Treated with antiviral therapies for influenza (eg, Tamiflu, Xofluza) within 28 days prior to Day 1. * Prior receipt of a pandemic influenza vaccine or participation in any pandemic influenza vaccine clinical study, including the mRNA-1018-P101 study. * Any medical, psychiatric, or occupational condition, that, in the opinion of the Investigator, might pose additional risk due to participation in …