  Background: Despite the consensus that vaccines play an important role in
combating the global spread of infectious diseases, vaccine inequity is still
rampant with deep-seated mentality of self-priority. This study aims to
evaluate the existence and possible outcomes of a more equitable global vaccine
distribution and explore a concrete incentive mechanism that promotes vaccine
equity. Methods: We design a metapopulation epidemiological model that
simultaneously considers global vaccine distribution and human mobility, which
is then calibrated by the number of infections and real-world vaccination
records during COVID-19 pandemic from March 2020 to July 2021. We explore the
possibility of the enlightened self-interest incentive mechanism, i.e.,
improving one's own epidemic outcomes by sharing vaccines with other countries,
by evaluating the number of infections and deaths under various vaccine sharing
strategies using the proposed model. To understand how these strategies affect
the national interests, we distinguish the imported and local cases for further
cost-benefit analyses that rationalize the enlightened self-interest incentive
mechanism behind vaccine sharing. ...
