A comparative analysis of supply chain factors impacting COVID-19 vaccine security in high-income countries (HICs) and low-income and middle-income countries (LMICs)

Our data suggest a stronger relationship between vaccine security and 'downstream' supply chain variables compared with 'upstream' variables. However, multiple outliers and the lack of an even stronger relationship suggests that there is no magic bullet for vaccine security. To boost vaccine resilience, countries must be well governed and strategically reinforce deficient aspects of their supply chains. Modest strength in multiple domains may be the best approach to counteracting the effect of an unfamiliar, novel pathogen.