Toward a grounded theory of why some immunization programmes in sub-Saharan Africa are more successful than others: a descriptive and exploratory assessment in six countries.

The question of why some immunization programmes in sub-Saharan Africa are more successful than others is an intriguing one, but not one that is frequently raised or investigated. Borrowing techniques from both performance benchmarking and positive deviance inquiry, we explored this question in six countries. We first set out to define for a systematic sample of countries the key constructs commonly associated with improving immunization coverage, using an inductive, 'insider' point of view. We then explored their utility in generating hypotheses about coverage differences across countries through a preliminary application of the measures of these constructs to the countries in this sample. Our findings suggest that there are different paths to success, and that not only what countries do, but how they execute their programmes, seem to make a difference in coverage outcomes. In some cases, extramural, contextual factors may also help to explain these differences. We discuss several hypotheses generated by our study, identify methodological limitations, and recommend improvements to the methods we used. Similar formative studies are needed to validate our preliminary hypotheses, to generate new ones, and to raise our level of confidence in the early policy implications that we see emerging from our preliminary work in this area. Eventually, testing of the hypotheses generated by this and other formative studies could generate a robust theory of why some programmes are more successful than others, a phenomenon likely to be relevant to other child and maternal health programmes in sub-Saharan Africa.