BARRIERS AND ENABLERS TO VACCINE DEPLOYMENT DURING PUBLIC HEALTH EMERGENCIES IN JIGAWA STATE, NIGERIA: A MIXED-METHODS CROSS-SECTIONAL STUDY

Background: Effective vaccine deployment during public health emergencies requires robust health system capacities and favorable socio-behavioral conditions. This study identified and analyzed the health system barriers and enablers influencing the effectiveness of emergency vaccine deployment in Jigawa State, Nigeria. Methods: A mixed-methods cross-sectional study was conducted. Quantitative data were collected from 619 healthcare workers, selected using stratified random sampling across five emirate councils in Jigawa State. A structured questionnaire, guided by the WHO Health System Building Blocks framework, was administered to assess associations between facility-level readiness indicators and vaccine deployment outcomes. Qualitative data were collected through 41 key informant interviews (KIIs) and focus group discussions (FGDs), analyzed thematically using NVivo 15, and guided by the Socio-Ecological Model (SEM). The two strands were integrated using a sequential explanatory strategy. Results: Quantitative analysis identified key health system barriers and enablers. At the bivariate level, ten factors, including emergency committee presence, functional cold chain equipment, regular supervisory support, dedicated emergency budgets, and structured community engagement, were each significantly associated with timely vaccine rollout. Multivariate logistic regression identified three independent predictors: absence of an emergency committee and absence of structured community engagement were independent barriers, while regular supervisory support was an independent enabler. The model demonstrated acceptable fit (Hosmer-Lemeshow p = 0.538) and fair discrimination (AUC-ROC = 0.731). Qualitative findings further identified governance fragmentation, supply chain disruptions, community mistrust, and workforce limitations as barriers. In contrast, traditional and religious leadership engagement, adaptive frontline practices, and integrated community microplanning emerged as key enablers. Conclusion: Governance structures, particularly emergency committee functionality and regular supervisory support, and community engagement are the strongest independent determinants of timely emergency vaccine deployment in Jigawa State. Addressing these barriers and leveraging these enablers through integrated, context-sensitive strategies is essential. This study contributes novel subnational, mixed-methods evidence from a high-need setting, offering an operational model transferable to similar low-resource contexts across Sub-Saharan Africa.