Critical success factors for high routine immunisation performance: a qualitative analysis of interviews and focus groups from Nepal, Senegal, and Zambia.

OBJECTIVES: Vaccination averts an estimated 2-3 million deaths annually. Although vaccine coverage improvements across Africa and South Asia have remained below global targets, several countries have outperformed their peers with significant increases in coverage. The objective of this study was to examine these countries' vaccination programmes and to identify and describe critical success factors that may have supported these improvements. DESIGN: Multiple case study design using qualitative research methods. SETTING: Three countries with high routine immunisation rates: Nepal, Senegal, and Zambia. PARTICIPANTS: We conducted 207 key informant interviews and 71 focus group discussions with a total of 678 participants. Participants were recruited from all levels, including government officials, health facility staff, frontline workers, community health workers, and parents. Participants were recruited from both urban and rural districts in Nepal, Senegal, and Zambia. RESULTS: Our data revealed that the critical success factors for vaccination programmes relied on the cultural, historical, and statutory context in which the interventions were delivered. In Nepal, Senegal, and Zambia, high immunisation coverage was driven by (1) strong governance structures and healthy policy environments; (2) adjacent successes in health system strengthening; (3) government-led community engagement initiatives, and (4) adaptation considering contextual factors at all levels of the health system. CONCLUSIONS: Throughout this project, our analysis returned to the importance of defining and understanding the context, governance, financing, and health systems within a country, rather than focusing on any one intervention. This paper augments findings from existing literature by highlighting how contextual factors impact implementation decisions that have led to improvements in childhood vaccine delivery. Findings from this research may help identify transferable lessons and support actionable recommendations to improve national immunisation coverage in other settings.