A Study to Investigate the Safety and Immunogenicity of mRNA-1469 in African Participants 1 to 65 Years of Age

The main objective of this trial is to evaluate the safety of mRNA-1469

Inclusion Criteria: For all participants: * In good general health or with stable chronic medical conditions, as determined by medical evaluation including medical history, physical examination, and laboratory tests. For participants 12 to 65 years of age: * Body mass index within the range 18 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. For participants 1 to 11 years of age: * Female participants who have reached menarche may be enrolled in the study if not pregnant or breastfeeding, subject to other criteria specified in the study protocol. For participants 1 to 4 years of age: * Participant was born born at ≥37 weeks gestation, with a minimum birth weight of 2.5 kg, without fetal growth restriction, and the participant's length and weight are both above the third percentile for age according to the WHO Child Growth Standard. Exclusion Criteria: For all participants: * 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 filovirus pathogens (including Ebola Zaire, Ebola Sudan, and Marburg). * 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. * Hepatitis B surface antigen (HBsAg) or Hepatitis C virus (HCV) Abs positive at Screening. * HIV infection, per local testing algorithm. * History of active tuberculosis requiring treatment in the past 3 years. * Acutely ill or febrile (temperature ≥38.0℃ \[100.4°F\]) within 72 hours prior to or at the Screening Visit or Day 1. * 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. For participants 12 to 65 years of age: * Abnormal Screening clinical laboratory values \>Grade 1 for total white blood cell count, hemoglobin, alanine aminotransferase, creatinine, or platelets. * Known history of poorly controlled hypertension (per determination of the Investigator), or systolic blood pressure \>160 mmHg at the Screening or Baseline (Day 1) visit. * Known history of hypotension or systolic blood pressure \