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

When the strategy of every individual is fixed, all individuals can be divided into two classes: susceptible individuals including laissez-faire individuals and a fraction 1 2 d of self-protective individuals (i.e., unsuccessful ones), and irrelevant individuals (equivalent to be removed from the system) including vaccinated ones and a fraction d of self-protective individuals that are selected to be successful and will not be infected in the following season of epidemic spreading. Among all susceptible individuals, I 0 individuals are randomly selected and set to be infected initially. The spreading dynamics follows the standard susceptible-infected-removed (SIR) model 40, 41 , where at each time step, each infected individual will infect all her susceptible neighbors with probability l, and then she will turn to be a removed individual with probability m. The spreading ends when no infected individual exists.