Place matters - the spatial diffusion of contagious diseases

The diffusion of contagious diseases follows a spatial pattern highly relevant for the design of intervention programs. This paper analyses the waves of a generic contagious disease in a pattern region. We develop a batch model based on a system dynamics model where the likelihood of an infection depends on distance from another person. The basic simulation shows a clear pattern of a wave sweeping over the region. Starting in one cell, the epidemic strongly depends on the proximity to the place of origin. The speed and intensiveness of the wave depends on the mobility, infectivity and contact rate, but also on the population pattern. Health policymakers have to install early detection and sentinel systems to stop an outbreak before it diffuses spatially. If it is possible to flatten the curve and prolong the diffusion process, barriers of vaccinated could be built up. This will also require controlling national and cross-border transport.