Phase 2/3 Trial of Vaccines Against Bundibugyo Virus Disease in Contacts of Cases in DRC

Inclusion Criteria: * A contact of a newly confirmed Bundibugyo virus disease (BVD) index case, occurring within the previous 21 days of enrollment. A contact is defined as a person who, within the previous 21 days, lived in the same household as the index case; OR visited or was visited by the index case at or after the onset of symptoms; OR, without using adequate personal protective equipment, provided the index case with care, was in close physical contact with the patient's body, body fluids, linen or clothes, or prepared the body for, or was exposed to the body at, a funeral ceremony. * Adults, adolescents, and children aged 12 years and older at the time of enrollment. * Capable of giving signed informed consent or assent, or having a parent or legal guardian capable of giving signed or witnessed verbal informed consent, in accordance with applicable country regulations. Exclusion Criteria: * History of laboratory-confirmed Bundibugyo virus disease. * Previous vaccination against Bundibugyo virus. Note: prior receipt of an Ebola or Marburg investigational or licensed vaccine is non-exclusionary provided that any prior vaccination was administered more than 28 days before enrollment and is documented. * History of anaphylaxis from a vaccine or a component of a vaccine. * Serious bed-confining illness requiring hospitalization at the time of vaccination. * Receipt of monoclonal antibodies as post-exposure prophylaxis (PEP) within 21 days prior to vaccination, or planned receipt after vaccination. * Ongoing treatment with antiviral PEP at the time of vaccination. Note: prior receipt of a licensed or experimental antiviral candidate for BVD PEP is acceptable provided the course was completed at least six days prior to vaccination. Note: if PEP becomes standard of care, it is non-exclusionary. * Use of any other experimental drug, other than antivirals or monoclonal antibodies used for BVD prophylaxis, within 28 days prior to vaccination. * Currently enrolled in, or planning to participate in, another investigational or interventional study during this study. Observational and registry studies are permitted. * Living in an area deemed inaccessible by the Investigator, for reasons of distance or security. * Symptoms consistent with BVD, defined as inexplicable bleeding, OR high fever together with at least three of the following: headache, lethargy, anorexia or loss of appetite, aching muscles or joints, stomach pain, difficulty swallowing, vomiting, difficulty breathing, diarrhea, hiccups.