Protocol: Identification and evaluation of critical factors in achieving high and sustained childhood immunization coverage in selected low- and lower-middle income countries

Abstract Introduction Increases in global childhood vaccine delivery have led to decreases in morbidity from vaccine-preventable diseases. However, these improvements in vaccination have been heterogeneous, with some countries demonstrating greater levels of change and sustainability. Understanding what these high-performing countries have done differently and how their decision-making processes will support targeted improvements in childhood vaccine delivery. Methods and analysis We studied three countries - Nepal, Senegal, Zambia - with exemplary improvements in coverage between 2000-2018 as part of the Exemplars in Global Health Program. We apply established implementation science frameworks to understand the “how” and “why” underlying improvements in vaccine delivery and coverage. Through mixed methods research we will identify drivers of catalytic change in vaccine coverage and the decision-making process supporting these interventions and activities. Methods include quantitative analysis of available datasets and in-depth interviews and focus groups with key stakeholders in the global, national, and sub-national government and non-governmental organization space, as well as community members and local health delivery system personnel. Ethics and dissemination Working as a multinational and multidisciplinary team, and under oversight from all partner and national-level (where applicable) institutional review boards, we collect data from participants who provided informed consent. Findings are disseminated through a variety of forms, including peer-reviewed manuscripts related to country-specific case studies and vaccine system domain-specific analyses, presentations to key stakeholders in the global vaccine delivery space, and narrative dissemination on the Exemplars.Health website. Strengths and limitations of this study This study is led by a multidisciplinary team and grounded in several theoretical frameworks across disciplines from implementation science to behavioral theory. We utilized a cross cutting, cross-disciplinary, approach, which assessed relevant domains across our selected exemplars countries as well as within the subjects that arise from the data, over a roughly 20-year time horizon. We selected three countries with historically high unvaccinated populations to represent different geographies, cultures, and governments, as well as to highlight regions with historically high unvaccinated populations. We did not study a less successful, or “non-exemplar”, counterfactual country. The research tools identified and explored catalytic events and the implementation of external policies and development of internal policies and systems, with a focus on participants’ current experiences and perceptions of prior activities.