A Study to Investigate the Safety, Reactogenicity, and Immunogenicity of mRNA-1469 Vaccine to Prevent Ebola-Bundibugyo Virus Disease in Healthy Adult Participants

Key Inclusion Criteria: * In good general health or with stable chronic medical conditions, as determined by medical evaluation including medical history, physical examination, and laboratory tests. * Body mass index within the range 18.5 to 39 kg/m2 (inclusive). * Female participants of childbearing potential may be enrolled in the study if not pregnant or breastfeeding, subject to other criteria specified in the study protocol. Key Exclusion Criteria: * History of anaphylaxis or severe hypersensitivity reaction requiring medical intervention after receipt of any mRNA vaccine or therapeutic, or any components of an mRNA vaccine or therapeutic. * History of participation in a prior vaccine study for pathogens causing Ebola virus disease. * History of confirmed or suspected filovirus exposure or infection or travel to an impacted area within 1 month prior to the Screening Visit (e.g. Ebola Zaire, Sudan, BDBV, and Marburg). * Other conditions that in the Investigator's opinion could interfere with interpretation of study results or limit the participant's participation in the study. * Acutely ill or febrile (temperature ≥38.0℃ \[100.4°F\]) within 72 hours prior to or at the Screening Visit or Day 1. * Abnormal screening clinical laboratory values \>Grade 1 for total white blood cell count, hemoglobin, alanine aminotransferase, aspartate aminotransferase, creatinine, alkaline phosphatase, total bilirubin, or platelets. * History of a diagnosis or condition that, in the judgment of the Investigator, is clinically unstable, potentially affects participant safety, the assessment of study endpoints, the assessment of immune response, or adherence to study procedures. Note: Other inclusion and exclusion criteria may apply.