This toolkit was developed using a structured, multistage process designed to ensure methodological rigour, policy relevance, and alignment with existing WHO guidance.

Scoping review of the literature

A scoping review was undertaken to identify existing normative guidance, regulatory frameworks, policy documents, and peer-reviewed literature relevant to vaccine product development, evaluation pathways, and policy translation. Electronic databases (including PubMed and Embase) and grey literature sources (including WHO vaccine position papers, recommendations from the WHO Strategic Advisory Group of Experts on Immunization, regulatory agency guidance, and product development partnership reports) were searched. Documents were screened for relevance to vaccine development pathways, correlates of protection, licensure considerations, post-licensure evaluation, and implementation planning. Findings were synthesized narratively to identify common themes, gaps in guidance, and areas requiring clarification or harmonization. The review prioritised globally applicable evidence, with attention to both high-income and low- and middle-income country contexts.

Drafting and internal technical review

An initial draft toolkit was developed based on the findings of the scoping review and structured around key decision points across the vaccine development and policy continuum. The draft was circulated for technical review within the WHO Immunization, Vaccines and Biologicals Department. Reviewers provided structured feedback on technical accuracy, clarity, consistency with existing WHO normative guidance, and feasibility of application across regulatory and programmatic settings. Revisions were incorporated iteratively to ensure alignment with WHO standards, terminology, and policy processes. 

External expert consultation and edorsement

The revised draft toolkit was submitted to the WHO Product Development for Vaccines Advisory Committee (PDVAC) for expert review. PDVAC members assessed the scientific rationale, policy coherence, and global applicability of the toolkit, with particular attention to its utility in supporting vaccine development pathways intended for use in diverse settings. Following incorporation of PDVAC feedback, the final version was presented to PDVAC and formally endorsed on 15 October 2025. 

The names and affiliations of all contributors and reviewers are listed in the Acknowledgements section.