Background

​Ebola virus disease (EVD) outbreaks, though sporadic, pose significant public health challenges due to high mortality rates and rapid transmission dynamics. A vaccine regimen has been developed by the client against disease caused by the Zaire ebolavirus species. While the regimen received regulatory approval and prequalification under exceptional circumstances based on immunobridging data, the lack of field effectiveness data remained a critical evidence gap. 

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Challenge

The client's primary challenge was identifying feasible methodologies for evaluating the real-world effectiveness of the vaccine regimen. Ethical considerations precluded traditional placebo-controlled trials, and sporadic outbreaks limited opportunities for large-scale studies. Rapid containment efforts, often using ring vaccination with an alternative vaccine, further complicated data collection efforts.

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Approach

A panel of 11 globally renowned experts was convened for a two-day virtual advisory board. To ensure alignment and provide comprehensive context, participants attended a pre-advisory board webinar. This session outlined the client’s clinical development programme, detailed the objectives of the advisory board, and introduced key discussion topics. A Q&A session at the end allowed participants to address any preliminary questions. 

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Outcomes

• ​The panel reviewed potential study designs, including cohort, case-control, and test-negative case-control methodologies and recommended the optimal design under current constraints.

• Experts highlighted the importance of proactively developing and pre-approving generic study protocols across high-risk countries to enable rapid implementation during outbreaks and underscored the need for large-scale preventive vaccination campaigns to create sufficient opportunities for effectiveness evaluation.

• The advisory board provided actionable strategies to navigate regulatory challenges, optimise study design, and enhance the client's ability to demonstrate vaccine efficacy under real-world conditions.