A Study to Evaluate the Safety and Immunogenicity of a Candidate Ebola Vaccine in Adults

The purpose of this study is to assess the safety and immunogenicity of the investigational ChAd3-EBO-Z vaccine administered to approximately 3 000 adults in Africa as a single IM dose Considering the risk of exposure to Ebola and the potential (based on animal data) for the investigational ChAd3-EBO-Z vaccine to afford at least partial protection, all subjects in the study will receive the investigational ChAd3-EBO-Z vaccine. The subjects in the Group EBO-Z will receive the vaccine at Day 0 of the study, whereas the subjects in the Group Placebo/ EBO-Z will receive a placebo at Day 0 (as a control) and will receive the investigational ChAd3-EBO-Z vaccine at Month 6, provided that no safety concerns are raised. In addition, vaccinating all subjects in the study with the investigational ChAd3 EBO Z vaccine will allow an increase of the safety database of the investigational vaccine. In case the geographic range of Ebola virus Zaire (EBOV) transmission expands to encompass any of the regions where this trial is conducted, earlier administration of the investigational ChAd3-EBO-Z vaccine to the subjects in the Group Placebo/ EBO-Z will be considered in that region.


Eligibility Criteria:
Inclusion Criteria:

* Subjects who, in the opinion of the Investigator, can and will comply with the requirements of the protocol (e.g. capability of or availability for Diary Card completion, return for follow-up visits, availability for clinical follow-up throughout the study period).
* Written/ thumb printed informed consent obtained from the subject prior to performing any study specific procedure or written/ thumb printed informed consent obtained from the subject's parent(s)/ legally acceptable representative(s) (LAR\[s\]) and written/ thumb printed informed assent obtained from the subject, for minor subjects. This will only be applicable for countries where the legal age of majority is ≥ 21 years.
* A male or female aged 18 years of age or older at the time of Screening.
* Healthy subjects as per Investigator judgement, as established by medical history, clinical examination and haematology/ biochemistry laboratory parameters screening before entering into the study.
* Female subjects of non-childbearing potential may be enrolled in the study.
* Non-childbearing potential is defined as pre-menarche, current tubal ligation, hysterectomy, ovariectomy or post-menopause.
* Female subjects of childbearing potential may be enrolled in the study, if the subject:
* has practiced adequate contraception for 30 days prior to the Day 0 visit, and
* has a negative pregnancy test at the Day 0 visit, and
* has agreed to continue adequate contraception until 30 days after the Month 6 visit.

Exclusion Criteria:

* Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine during the period starting 30 days before the Day 0 visit, or planned use during the study period.
* Previous vaccination with an investigational EBOV or Marburg vaccine, or previous vaccination with a chimpanzee adenoviral vectored investigational vaccine.
* Known prior EBOV or SUDV disease.
* Travel to a country affected by the EBOV epidemic or direct contact with a person with EVD within 21 days prior to the Day 0 visit.
* History of any reaction or hypersensitivity (such as anaphylaxis, urticaria \[hives\], respiratory difficulty, angioedema, or abdominal pain) likely to be exacerbated by any component of the study vaccine.
* Planned administration/ administration of a vaccine not foreseen by the study protocol in the period starting 30 days before and ending 30 days after each vaccination visit.
* Serious acute or chronic illness determined by medical history and clinical examination including, but not limited to:

  * Clinically significant immunosuppressive or immunodeficient condition (e.g. clinical acquired immune deficiency syndrome \[AIDS\]).
  * Any clinically significant haematological (CBC, including differential count and platelet count) or biochemical (ALT, creatinine) laboratory abnormality.
  * Any chronic illness with recent signs of exacerbation, or imposing a change in the chronic treatment regimen, within 3 months prior to the Day 0 visit.
  * Any unstable chronic medical condition (e.g. uncontrolled asthma).
* Pregnant female.