Vaccine-preventable disease and the under-utilization of immunizations in complex humanitarian emergencies

Complex humanitarian emergencies affect 40-60 million people annually and are a growing public health concern worldwide. Despite efforts to provide medical and public health services to populations affected by complex emergencies, significant morbidity and mortality persist. Measles is a major communicable disease threat, but through vaccination of broader target age groups beyond the traditional immunization schedule, measles-related mortality has been significantly reduced during crises. Yet, a limited number of vaccine-preventable diseases continue to contribute disproportionately to morbidity and mortality in complex emergencies. The literature suggests that Streptococcus pneumoniae, Rotavirus, and Haemophilus influenzae type-b should be key targets for vaccination programs. Because of the significant contribution of these three pathogens to complex humanitarian emergencies in low and middle-income countries regardless of disaster type, geography, or population, their vaccines should be considered essential components of the standard emergency response effort. We discuss the barriers to vaccine distribution and provide evidence for strategies to improve distribution, including expanded target age-range and reduced dose schedules. Our review includes specific recommendations for the expanded use of these three vaccines in complex emergencies in low and middle-income countries as a way to guide future policy discussions.