INTRODUCTION:
Nigeria contributes disproportionately to the global zero‑dose (unvaccinated) burden, with persistent subnational inequities despite repeated immunization campaigns.¹ Evidence on how individual, community, and structural mobility barriers interact to exacerbate zero‑dose clustering remains limited. This study examines spatiotemporal patterns and the compound effects of mobility restrictions and socioeconomic disadvantage on zero‑dose prevalence in Nigeria.

METHODS:
We analyzed four waves of the Nigeria Demographic and Health Survey (2008–2024). Spatial clustering was assessed using global moran’s I and local indicators of spatial association (LISA).² Multilevel logistic regression (n=19962) estimated adjusted odds ratios (aOR) for individual and community determinants. A restricted mobility index was developed at state level using principal component analysis, capturing barriers related to distance, permission, and required companionship.³'⁴ The geographical detector q‑statistic quantified the independent and interactive effects of mobility and structural characteristics including maternal education, poverty, human development index (HDI), and geopolitical zone.⁵

RESULTS:
Significant non-random spatial clustering was observed (moran’s I = 0.609; p < 0.001), revealing persistent hotspots of zero-dose children concentrated in north-west Nigeria, while coldspots were predominantly located in the southern region. Key individual protective factors included institutional delivery (aOR=0.44; [95% CI=0.36–0.52]), ≥4 antenatal visits (aOR=0.40; [0.35–0.45]), and maternal education above secondary level (aOR=0.41; [0.36–0.46]). Community‑level high ANC‑utilization clusters further reduced odds (aOR=0.61; [0.52–0.72]). At state level, maternal education (q=0.64) and geopolitical zone (q=0.59) explained the most spatial heterogeneity. Mobility had a modest independent effect (q=0.12), but strong nonlinear‑enhancement interactions emerged between mobility and education (q=0.91), geopolitical zone (q=0.87), and HDI (q=0.79).

CONCLUSIONS:
Zero‑dose clustering in Nigeria reflects entrenched structural inequities, where restricted mobility amplifies rather than independently drives the effects of low maternal education and regional disadvantage. Addressing zero‑dose prevalence requires shifting from logistics‑focused approaches toward integrated strategies that combine immunization delivery with female educational empowerment and geographically targeted support for high‑burden hotspots.