A Prioritised Research Agenda to Inform the Introduction and Use of Lassa fever vaccines in West Africa

Objective:Lassa fever is a viral haemorrhagic disease endemic in West Africa.While several vaccine candidates are in development, evidence to guide policy-and decisionmaking on vaccines remains limited.We convened a Policy Research Working Group (PRWG) to develop a prioritised research agenda to reduce delays related to policy-and decision-making. Methods:Using the Child Health and Nutrition Research Initiative (CHNRI) methodology, we conducted a two-phase prioritisation exercise.First, a rapid assessment of literature and expert interviews was conducted to identify evidence gaps, which were refined into 29 questions across four thematic categories.In phase two, 235 experts scored these questions using five criteria. Results:Research Priority Scores (RPS) ranged from 80-92%, indicating the importance of the identified research questions.Thirteen research questions were prioritised, focusing on defining vaccination target groups, assessing vaccine efficacy in special populations, evaluating economic impact, and understanding vaccine acceptance.High expert agreement (67-85%) reinforced the robustness of the prioritisation outcomes. Conclusions:This stakeholder-driven agenda highlights the most critical evidence needs to guide vaccination policies, national decision-making, and implementation planning for future Lassa fever vaccines.Early alignment between research and policy can accelerate vaccine introduction and ensure equitable access in endemic regions.