CEPI Workshop Report: Applying Disease X Vaccine Library and Knowledge Base Approaches to Severe Fever with Thrombocytopenia Syndrome (SFTS).

On 9-10 December 2025, the Coalition for Epidemic Preparedness Innovations (CEPI) and the International Vaccine Institute (IVI) convened a workshop in Seoul under CEPI's Disease X Program. The primary objective was to identify existing gaps needing to be filled and streamline vaccine development and preparedness for Severe Fever with Thrombocytopenia Syndrome (SFTS). CEPI's partners and experts discussed a multifaceted agenda, ranging from understanding the evolving epidemiology to the refinement of animal models and immunological assay harmonization. Key outcomes included the refinement of Target Product Profiles (TPPs) specifying use cases for both peacetime and outbreak contexts, alongside a recommendation for a core immunoassay panel aimed at harmonizing evaluation frameworks and mitigating the challenges posed by low SFTS prevalence. Integration of the One Health approach emerged as a critical strategy for SFTS prevention, complemented by proactive regulatory engagement to compress vaccine development timelines. This report summarizes these key insights from the workshop, delineating a strategic framework for delivering safe, effective, and accessible vaccines for SFTS and broader Disease X threats.