Evolutionary vaccination game considering intra-seasonal strategy shifts regarding multi-seasonal epidemic spreading

During multi-seasonal epidemics, analyzing the individual voluntary vaccination strategy and understanding its evolutionary patterns are crucial for controlling epidemic spreading. To this end, we construct a two-layer spreading network comprising awareness and epidemic subnets, and then propose a novel epidemic spreading model, termed the model UAU−SDVSCIR. Based on the model, intra-seasonal vaccination strategy shifts are driven by the individual perception of infection risk, while between epidemic seasons, vaccination behavior is described by inter-seasonal vaccination games with individual-based risk assessment (IB-RA) and strategy-based risk assessment (SB-RA) rules, respectively. We propose an immunity discount factor to represent the herd immunity effect and conduct theoretical analysis using Microscopic Markov Chain Approach (MMCA). By carrying out extensive numerical simulations, some results are obtained. Incorporating the herd immunity effect in MMCA theoretical analysis is both rational and effective. After each single-season epidemic, compared to the IB-RA rule, individuals taking the SB-RA rule are more sensitive to the effectiveness and cost of vaccine. For multi-seasonal epidemic spreading, individuals adhering to the IB-RA gradually increase their vaccination rate, eventually reaching an equilibrium. Conversely, with certain parameters, SB-RA may cause group fluctuations and prevent reaching a single equilibrium. Additionally, for SB-RA, the vaccine coverage rate is generally lower across most of the vaccine parameters.