Braess's Paradox in Epidemic Game: Better Condition Results in Less Payoff

Zhang, Hai-Feng; Yang, Zimo; Wu, Zhi-Xi; Wang, Bing-Hong; Zhou, Tao

As mentioned above, in most related works, individuals are usually divided into two opposite classes: vaccinated and laissez-faire, while less attention is paid on other alterative strategies in between. In this paper, we propose an evolutionary epidemic game model to study the effects of self-protection on the system payoff and epidemic size. We find a counter-intuitive phenomenon analogous to the well-known Braess's Paradox 20 in network traffic dynamics, that is, the increasing of successful rate of self-protection may, on the contrary, decrease the system payoff. We provide a mean-field solution, which well reproduces such observation. This study raises an unprecedent challenge on how to guide the masses of people to react to the outbreaks of infectious diseases, since sufficient knowledge about and effective protecting skills to the infectious disease, which sound very helpful for every individual, may eventually enlarge the epidemic size and cause losses for the society. The model details are described in the Methods section, while here we proceed with presenting the results.