ABSTRACT
By January 2022, the COVAX international vaccine collaboration had allocated over a billion vaccines to over 140 countries. We describe and review the allocation process chosen, which reflected both an objective of equitably distributing vaccines across the world and the need to fund that mission. We show how vaccine supply limitations and constraints on some countries' absorptive capacity have affected overall allocative outcomes. We also discuss market design approaches that were considered but not implemented, including the use of an exchange mechanism to better match countries' vaccine allocations to their preferences, as well as a vaccine brokerage under which countries could sell excess vaccines to countries with ongoing need. Our analysis addresses some criticisms of COVAX, and offers suggestions for agencies organizing global vaccine cooperation for future pandemics.