Modeling Voluntary Influenza Vaccination Using an Age-Structured Inductive Reasoning Game

Recently, the impact of social behavior on the dynamics of voluntary vaccination coverage against seasonal influenza has been modeled using inductive reasoning games. This modeling technique allows for a natural approach to describing decision making, experience, and adaptation of individuals. However, so far, age structure has not been included in this type of models, despite the fundamental role that age plays in influenza epidemiology. Here, we build on the previous mathematical framework to include this feature missing from inductive reasoning games. Then, we discuss several results in contrast to previously developed theory. We find that including age structure may impact on the game dynamics not only for epidemiological, but also behavioral reasons. Although implausible for realistic parameter values, age structure allows for the possibility that individuals eliminate influenza through voluntary vaccination. Furthermore, we find that, in this case, period doubling is not the only type of generic bifurcation that could account for the stability loss of mean-field fixed-point dynamics of the vaccination coverage. Our study emphasizes the importance of including age structure in predictive models of voluntary vaccination against seasonal influenza.