  In this early draft, we provide an overview on similarities and differences
in the implementation of a paper card-based vaccine credential system and an
app-based vaccine credential system. A vaccine credential's primary goal is to
regulate entry and ensure safety of individuals within densely packed public
locations and workspaces. This is critical for containing the rapid spread of
Covid-19 in densely packed public locations since a single individual can
infect a large majority of people in a crowd. A vaccine credential can also
provide information such as an individual's Covid-19 vaccination history and
adverse symptom reaction history to judge their potential impact on the overall
health of individuals within densely packed public locations and workspaces.
After completing the comparisons, we believe a card-based implementation will
benefit regions with less socioeconomic mobility, limited resources, and
stagnant administrations. An app-based implementation on the other hand will
benefit regions with equitable internet access and lower technological divide.
We also believe an interoperable system of both credential systems will work
best for regions with enormous working-class populations and dense housing
clusters.
