Health systems constraints and facilitators of national immunization programs in low- and middle- income countries

Abstract

Like most health interventions, National Immunization Programs (NIPs) are embedded within health systems. This means that NIPs and health systems exist in a constant interaction. Vaccine preventable diseases are widely recognized as the chief cause of morbidity, disability and mortality worldwide and NIPs are understood to be one of the most cost-effective interventions against this burden. In low and middle- income countries (LMICs), where the burden of disease is high, NIPs have been reported to perform at suboptimal levels. It has been suggested that this suboptimal performance of NIPs can be associated with the poor state of health systems in LMIC. Despite this, the interaction between NIPs and health systems is poorly understood. In addition to this, systematic evidence on how health systems constraints and facilitators impact on the performance of NIPs in LMICs is scarce. To address this evidence gap, a systematic review study was conducted, that involved an initial scoping review of the evidence-base on NIPs and health systems in LMICs from which a logic model was developed. This logic model was then applied as a guide for a qualitative systematic review aimed at assessing the health systems constraints and facilitators of NIP performance in sub-Saharan Africa. The findings of this review suggest that well-performing NIPs are those that operate within enabling health systems, characterized by the availability of strong political endorsement for vaccines, clear governance structures and effective collaboration with global partners. Despite this, significant health systems constraints persist and include the limited capacity of health workers in sub-Saharan Africa, weak country infrastructure, poor service delivery, inadequate vaccine communication and ineffective community engagement in immunization programs. This systematic review study contributes to our limited understanding of the interaction between NIPs and health systems. In addition, the findings show how system-wide constraints and facilitators impact on the performance of NIPs. These findings have relevance for ongoing health systems strengthening initiatives, especially where NIPs are concerned.