  The temporal evolution of a contagious viral disease is modelled as the
dynamic progression of different classes of population with individuals
interacting pairwise. This interaction follows a binary mechanism typical of
kinetic theory, wherein agents aim to improve their condition with respect to a
mutual utility target. To this end, we introduce kinetic equations of
Boltzmann-type to describe the time evolution of the probability distributions
of the multi-agent system. The interactions between agents are defined using
principles from price theory, specifically employing Cobb-Douglas utility
functions for binary exchange and the Edgeworth box to depict the common
exchange area where utility increases for both agents. Several numerical
experiments presented in the paper highlight the significance of this mechanism
in driving the phenomenon toward endemicity.
