Immune Durability After VSV-EBOV Vaccination

Study Overview
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Brief Summary
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This prospective observational cohort study will follow the roughly 100 adults who received the VSV-ZEBOV vaccine in the Geneva phase 1 randomized controlled trial in 2014-2015 in order to determine their long-term (5-year) immune response to vaccination.

Detailed Description
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Background: During the Ebola epidemic of 2014-5, there was no proven therapy or prevention available beyond horizontal infection control measures. After the Canadian government donated 800 vials of the vaccine candidate VSV-EBOV to World Health Organization (WHO), the University Hospitals of Geneva agreed to perform a WHO-coordinated phase I/II double-blind, placebo-controlled randomized trial to assess the candidate's safety and immunogenicity healthy adult volunteers. The doses of 10 E7 pfu and 5 x 10 E7 pfu were tested in 35 and 16 volunteers, respectively, before a safety-driven study hold in late 2014. At trial resumption in early 2015, the remaining volunteers (n=51) received 3 x 10 E5 pfu. Thirteen volunteers received placebo. Among vaccinees, early immune responses were impressive, even at the lowest dose of 3 x 10 E5 pfu, and persisted well up to 6 months (last time point assessed). The trial successfully ended 12 months after injection. This prospective observational study will assess immune durability in this group of vaccinees at yearly time points up to five years post-vaccination.

Official Title
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Long-term Immune Durability After Vaccination With the Vesicular Stomatitis Virus-vectored Zaire Ebola Candidate Vaccine (VSV-EBOV): a Prospective Observational Cohort Study

Conditions
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Immune Response, Vaccination, Durability

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participated and was vaccinated with a single injection of VSV-EBOV at a dose of either 3 x 10E5 pfu, 10E7 pfu or 5 x 10E7 pfu in the Geneva phase I VSV-EBOV vaccine trial (NCT02287480). Able to provide written, informed consent for this observational study. Exclusion Criteria: Received additional vaccination with VSV-EBOV at similar or differing doses. Was lost to follow-up in the Geneva phase I VSV-EBOV vaccine trial

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 68 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| vaccinated with 5 x 10E7 pfu VSV-ZEBOV<br>Volunteers vaccinated in 2014 or 2015 with 5 x 10E7 pfu VSV-ZEBOV | |
| vaccinated with 10E7 pfu VSV-ZEBOV<br>Volunteers vaccinated in 2014 or 2015 with 10E7 pfu VSV-ZEBOV | |
| vaccinated with 3 x 10E5 pfu VSV-ZEBOV<br>Volunteers vaccinated in 2014 or 2015 with 3 x 10E5 pfu VSV-ZEBOV | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EBOV-specific IgG antibody titers measured by ELISA |  | 5 years after vaccination | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EBOV-specific IgG antibody titers measured by ELISA |  | 2, 3, and 4 years after vaccination |