Gavi's Zero-Dose Learning Hubs: enhanced approach for evidence generation and use from local to global.

Reaching and fully immunizing zero-dose (ZD) children and missed communities is at the core of the Gavi, The Vaccine Alliance 5.0/5.1 and Immunization Agenda 2030 strategies. This is critical to ensure equitable immunization coverage and access to other primary health care services and to prevent outbreaks. The diversity of settings where these children live and the complexity of vaccination barriers require a complementary set of activities embedded in national systems. Learning approaches are needed to use evidence to improve equity and reach. Gavi has helped fill this gap with the Zero-Dose Learning Hub (ZDLH) initiative, which is composed of consortia partners in four countries-Mali, Nigeria, Uganda, and Bangladesh-and a global-level consortium. This paper describes the ZDLH design, theory of change, methods, and measures of success. Then, future papers will present ZDLH results, successes and challenges, and recommendations. The ZDLH initiative is prospective and runs through 2025. It features primary evidence generation through rapid assessments, improved monitoring, implementation research in targeted subnational areas where ZD children are located, and country-specific learning agendas and knowledge translation activities to facilitate evidence use. The global-level consortium offers technical assistance to country learning hubs and facilitates synthesis, dissemination, and improves evidence use across low- and middle-income countries. A common measurement, evaluation, and learning plan documents whether evidence is generated and used and how the overall model works to inform future adaptation. Target audiences for evidence are the Gavi Board; Gavi strategy, programme, and country teams; countries' ministry of health and immunization programmes at national and subnational level; and other donors and implementing partners working to improve immunization equity. The ZDLH initiative is a coherent approach to evidence generation and learning, and the implementation experience informs how to better design and support learning systems embedded within National Health Systems.