Abstract
Nigeria has one of the highest burdens of zero-dose children globally, particularly in underserved and hard-to-reach communities where routine immunisation systems face persistent barriers. In Niger state, these challenges are compounded by insecurity, seasonal flooding and dispersed populations, limiting the effectiveness of conventional facility-based approaches. We describe the implementation of the Strengthening Routine Immunization in Consequential Areas of Niger State (STRICAN) initiative, which applied a precision immunisation approach to identify and reach previously unreached children. The model combined household-level enumeration, geographical information system-enabled microplanning through a digital Micro Coverage Tracking Tool and community-based mobilisation using Community Health Influencers, Promoters, and Services agents and local leadership structures. Across 10 local government areas, the initiative generated granular data on settlements and under-five children, enabling targeted service delivery through a mix of outreach, mobile and facility-based strategies. Vaccination activities were adapted in real time to contextual challenges, including insecurity, poor network connectivity and population displacement. This implementation experience highlights the importance of integrating digital tools with trusted community systems to improve identification, tracking and service delivery for zero-dose populations. Key lessons include the value of data-driven microplanning, flexible delivery strategies in fragile settings and strong partnerships between government and implementing actors. The STRICAN model offers practical insights for policymakers and programme implementers seeking to strengthen routine immunisation systems and reach underserved populations in similar contexts.