Ebola Sudan Chimpanzee Adenovirus Vector Vaccine in Healthy Adults

Inclusion Criteria: 1. 18 to 50 years old. 2. Available for clinical follow-up through Week 48 after enrollment. 3. Able to provide proof of identity to the satisfaction of the study clinician completing the enrollment process. 4. Able and willing to provide fingerprints and have their photographs taken including injection site photographs. 5. Must allow home visits 6. Must complete an Assessment of Understanding (AoU) prior to enrollment by answering 9 out of 10 questions at least once in 3 attempts. 7. Able to read (English or Luganda) and willing to complete the informed consent process. 8. In good general health without clinically significant medical history. 9. Physical examination and laboratory results without clinically significant findings and a body mass index (BMI) ≤ 40 within the 56 days prior to enrollment. 10. Laboratory Criteria within 56 days prior to enrollment: 1. Hemoglobin ≥ 11.0 g/dL for women; ≥12.5 g/dL for men. 2. White blood cells (WBC) = 2,500-12,000 cells/mm\^3. 3. Total lymphocyte count ≥ 800 cells/mm\^3. 4. Platelets = 125,000 - 400,000/mm\^3. 5. Alanine aminotransferase (ALT) ≤ 1.25 x upper limit of normal. 6. Serum creatinine ≤ 1 x upper limit of normal. 7. HIV-uninfected as evidenced by a negative FDA-approved HIV diagnostic test. Female-Specific Criteria: 11. Negative β-HCG (human chorionic gonadotropin) pregnancy test; serum β-HCG at screening and urine β-HCG at enrollment if woman is of reproductive potential. 12. Agrees to use an effective means of birth control from at least 21 days prior to enrollment through 24 weeks after study vaccination if assessed to be of reproductive potential. Exclusion Criteria: Volunteer has received any of the following substances: 1. Investigational Ebola or Marburg vaccine in a prior clinical trial or prior receipt of a cAd3 adenoviral vectored investigational vaccine. 2. Chronic use of immunomodulators and systemic glucocorticoids in daily doses of glucocorticoid equivalence \> 20 mg of prednisolone, for periods exceeding 10 days. Non-steroidal anti-inflammatory drugs \[NSAIDS\] are permitted. Participants that have used less than the stated glucocorticoid dose may still be excluded at the Investigator's discretion. 3. Blood products within 112 days (16 weeks) prior to enrollment. 4. Investigational research agents within 28 days (4 weeks) prior to enrollment. 5. Live attenuated vaccines within 28 days (4 weeks) prior to enrollment. 6. Subunit or killed vaccines within 14 days (2 weeks) prior to enrollment. 7. Current anti-tuberculosis prophylaxis or therapy. Female-specific criteria: 8. Woman who is pregnant, breast-feeding or planning to become pregnant during the first 24 weeks after study vaccine administration. Volunteer has a history of any of the following clinically significant conditions: 9. Serious adverse reactions to vaccines such as anaphylaxis, urticaria (hives), respiratory difficulty, angioedema, or abdominal pain. 10. Allergic reaction to excipients in the study vaccine including gentamycin, neomycin or streptomycin. 11. Clinically significant autoimmune disease or immunodeficiency. 12. Asthma that is not well controlled. 13. Positive result on a rapid plasma reagin (RPR) test. 14. Diabetes mellitus (type I or II). 15. Thyroid disease that is not well controlled. 16. A history of hereditary angioedema (HAE), acquired angioedema (AAE), or idiopathic forms of angioedema. 17. Idiopathic urticaria within the last 1 year. 18. Hypertension that is not well controlled. 19. Bleeding disorder diagnosed by a doctor (e.g. factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with IM injections or blood draws. 20. A malignancy that is active, currently being treated, or not surgically cured. 21. Seizure in the past 3 years or treatment for seizure disorder in the past 3 years. 22. Asplenia or functional asplenia. 23. Psychiatric condition that precludes compliance with the protocol; past or present psychoses; or within five years prior to enrollment, history of a suicide plan or attempt. 24. Any medical, psychiatric, social condition, occupational reason or other responsibility that, in the judgment of the investigator, is a contraindication to protocol participation or impairs a volunteer's ability to give informed consent.