  Vaccine delivery in under-resourced locations with security risks is not just
challenging but also life threatening. The current COVID pandemic and the need
to vaccinate have added even more urgency to this issue. Motivated by this
problem, we propose a general framework to set-up limited temporary
(vaccination) centers that balance physical security and desired (vaccine)
service coverage with limited resources. We set-up the problem as a Stackelberg
game between the centers operator (defender) and an adversary, where the set of
centers is not fixed a priori but is part of the decision output. This results
in a mixed combinatorial and continuous optimization problem. As part of our
scalable approximation of this problem, we provide a fundamental contribution
by identifying general duality conditions of switching max and min when both
discrete and continuous variables are involved. We perform detailed experiments
to show that the solution proposed is scalable in practice.
