Governing the 'Big Catch-up': A Critical Policy Analysis of Immunisation Equity and Governance Frameworks in Post-Crisis Sierra Leone

Abstract Background The COVID-19 pandemic caused a historic backslide in global pediatric vaccinations, leaving millions of "zero-dose" children at risk. In response, global health partners launched the "Big Catch-up" (BCU) initiative. While the BCU aims to restore coverage, the governance frameworks that translate these global mandates into local realities in resource-constrained, post-crisis settings remain under-scrutinised. This study examines how immunisation equity is conceptualised and implemented in Sierra Leone. Methods Using a Qualitative Critical Policy Analysis (CPA) grounded in Carol Bacchi’s "What’s the Problem Represented to be?" (WPR) framework, this study analysed a policy archive of Sierra Leone’s national health strategies, immunisation blueprints, and donor framework documents (2019–2025). The analysis focused on uncovering underlying assumptions, silences, and the discursive effects of current governance structures. Results The analysis revealed four key thematic tensions: (1) a representation of "problematic dependency" that silences the need for domestic resource mobilisation; (2) a "technical Verticalisation" that reduces equity to a cold-chain logistics problem; (3) a governance paradox where decentralised responsibility for zero-dose targets is met with centralised fiscal control; and (4) the reinforcement of the "Inverse Care Law," where rurality is treated as a logistical hurdle rather than a site of structural neglect. Conclusions Current governance frameworks prioritise technical efficiency and donor alignment over structural justice. To ensure the "Big Catch-up" sustains long-term equity, policy redesign must shift from reactive mobile outreach toward permanent rural health infrastructure and genuine fiscal decentralisation. This study provides a roadmap for moving beyond numerical coverage metrics toward a governance model rooted in structural health rights.