Immunisations are among the most powerful public health interventions, and significant progress has been made to improve access to vaccines for children in low- and middleincome countries. Despite these global efforts, approximately 14.5 million children did not receive any vaccination (zero dose) in 2023 and another 6.5 million children were under-immunised, with significant disparity among and within countries . In Nigeria, vaccination rates lag behind the global average, with children in hard-to-reach areas including conflict zones and geographically isolated areas having disproportionately lower immunisation coverage rates . In these areas, settlements are sometimes scattered, often with poor infrastructure (e.g., road networks). The population may also be nomadic with high mobility impacting fixed population denominator data used for planning.

Kano and Kaduna states in Northwest Nigeria face significant immunisation challenges, where an estimated 27% of children in these areas are unvaccinated. There is a large hard-to-reach and nomadic population in both states. In order to reach these children, health system managers must have a clear understanding of where children are located to enable effective planning for routine immunisations and outreach campaigns. This has traditionally been done by using hand-drawn maps relying on health workers’ knowledge of the geographic areas in which they work, which are prone to errors and do not provide reliable information for planning.

Geospatial mapping is a visualisation method that enables the creation of customised maps that display geospatial data on populations, settlements, subnational boundaries and infrastructure which can be used by health system managers to identify elements such as missed settlements, health facilities and available roads to support microplanning processes for immunisation programs. This technology can help to identify communities that may otherwise be missed, where high numbers of zero-dose or under-immunised children are often located. Research has found that geospatial maps show better usability and accuracy compared to hand-drawn equivalents. A recent report mapped key Universal Health Coverage (UHC) contributions of geospatial technology and data to include microplanning for targeted awareness creation and campaign planning; vaccination session tracking; campaign monitoring; vaccination coverage modelling; disease surveillance; health systems service point mapping; geographic accessibility modelling; and population estimation & spatial distribution .