Vaccination strategies in a two-layer SIR/V–UA epidemic model with costly information and buzz effect

The promptness with which individuals respond to information has an important effect on the spread of epidemics. To study this effect, we establish a two-layer SIR/V epidemic model that incorporates the effects of information buzz and information costs in the framework of a vaccination game. Previous studies on this issue have generally assumed that only unaware people can become aware, and the relative vaccination cost is used to update their strategies for avoiding infection. Firstly, we introduce the idea that aware people can also become unaware because of a wicked rumor about a beneficial practice. Secondly, the relative cost of information is modeled for individual update strategies in a novel way of framing a game by introducing a two-strategy and 2 (information state A/UA) by 2(healthy/infected) state game, referred to as a two-under-two game. In this framework, susceptible, infected, and vaccinated individuals are divided into two states as unaware and aware, and recovered individuals are assumed to be aware, for an unbounded and well-mixed population. Information about wearing masks or taking other protection against diseases spreads locally for a season, and this information has a significant tendency to reduce the extent of contagious disease that persists through each generation of the model. Mathematical analysis shows that funds spent on awareness can reduce the vaccination cost and improve the epidemic threshold under certain conditions.