  Vaccination has been proven to be the most effective method to prevent
infectious diseases. However, there are still millions of children in low and
middle-income countries who are not covered by routine vaccines and remain at
risk. The World Health Organization - Expanded Programme on Immunization
(WHO-EPI) was designed to provide universal childhood vaccine access for
children across the world and in this work, we address the design of the
distribution network for WHO-EPI vaccines. In particular, we formulate the
network design problem as a mixed integer program (MIP) and present a new
algorithm for typical problems that are too large to be solved using commercial
MIP software. We test the algorithm using data derived from four different
countries in sub-Saharan Africa and show that the algorithm is able to obtain
high-quality solutions for even the largest problems within a few minutes.
