Challenges of vaccine presentation and delivery: How can we design vaccines to have optimal programmatic impact?

Immunization program delivery strategies that enable high vaccine coverage, particularly in inaccessible and remote areas, are critical to achieving optimal vaccine impact. In addition to demonstration of safety and efficacy, there are many factors that influence whether a newly licensed vaccine will be introduced into a country's national immunization program, particularly in resource-constrained environments. This paper describes three case studies of novel approaches that represent the potential for improved programmatic impact by increasing vaccine accessibility in different ways. However, the pathway to regulatory approval, policy recommendation, and program introduction in low- and middle-income countries is complex, requiring engagement with multiple, diverse stakeholders. Consideration of aspects that affect uptake in low- and middle-income countries, during the product development stage, will help better position new or second-generation vaccine products for successful implementation to achieve public health impact.