A Systems-Based Framework for Immunisation System Design: Six Loops, Three Flows, Two Paradigms

Despite massive progress in vaccine coverage globally, the region of sub-Saharan Africa is lagging behind and not on track for Sustainable Development Goal 3 by 2030. Subnational under-immunisation, related to geographical and social heterogeneity, is part of the problem. System-wide changes could transform current immunisation systems to become more sustainable, resilient and inclusive. A framework is proposed that captures the complexity of immunisation systems and offers directions for sustainable redesign. Insights were extracted from literature, stakeholder workshops, and field research in Rwanda and Kenya. A conceptual model of the national immunisation system was co-developed and validated with stakeholders. Leverage points were suggested for intervention scenario building. The Immunisation System Diagram assembles the paradigms of planned and emergency immunisation in one system and emphasizes the synchronized flows of vaccine receiver, vaccinator and vaccine. Six feedback loops capture the main subsystems. Sustainability and resilience are assessed based on loop dominance and dependency on exogenous factors such as donor funding and vaccine stockpiles. In group model building workshops, the diagram invites stakeholders to share their mental models, to assess the system’s performance and to trigger detection of root causes and leverage points. The framework provides a systems-approach for problem structuring and policy design.