A Learning Agenda to Address Immunization Equity and Access for Nigeria to End Zero-Dose Children by 2030: Report from a National Stakeholder Consensus Workshop.

Background: Nigeria has one of the highest burdens of zero-dose (ZD) children, those who have not received the first dose of pentavalent vaccine, despite multiple national and partner initiatives to strengthen routine immunization. A coordinated national learning agenda is required to guide evidence generation and use for reducing ZD children. The study objective is to describe the process and outcomes of a national stakeholder workshop that used a modified Delphi approach to prioritise learning questions on ZD children in Nigeria. Methodology: The Zero-Dose Learning Hub (ZDLH) convened a national workshop of immunization stakeholders from government, development partners, and civil society. A three-round modified Delphi process was used. In Round 1 (pre-workshop), participants independently scored learning questions derived from global Gavi learning priorities and Nigerian political-economy analyses. In Round 2 (during the workshop), participants discussed and re-scored questions in plenary and small groups. In Round 3 (post-workshop), participants completed a final independent ranking. Results: Ten learning questions were prioritised under three themes: equity, health systems, and innovation. The highest-ranked questions consistently focused on identifying and monitoring zero-dose & under-immunised children; understanding who and where they are and why they are missed; and health-system factors influencing their identification and measurement. Community engagement, data harmonisation, and capacity-building emerged as secondary but important areas. Conclusion: The workshop generated a nationally owned learning agenda that highlights Nigeria's most urgent evidence needs for reaching ZD children. The prioritised questions provide a practical roadmap for NPHCDA and partners to strengthen immunization equity, guide operational research, and support targeted programme implementation.