An evolutionary game model of disease-vaccination strategy in multiplex hypernetwork

During epidemics, behavioral and psychological convergence within societies significantly influences the formation of herd immunity. To investigate the interaction between individual vaccination strategies and disease transmission, this study constructs a two-layer dynamic hypernetwork model coupling disease spread with vaccination behavior: the upper layer represents strategy update, while the lower layer governs disease transmission dynamics. First, disease transmission is simulated using a mean-field compartmental model incorporating nonlinear infection rates and interaction coupling terms. Second, evolutionary game theory is applied to analyze vaccination strategy evolution. Findings reveal that conformity suppresses herd immunity formation; excessive conformity not only weakens collective cooperation but also increases average societal costs. Experiments further confirm: disease transmission is influenced by upper-layer decisions, while cooperation levels in the strategy layer are regulated by lower-layer transmission parameters. Vaccination rates do not monotonically increase with decreasing costs but are affected by multiple interacting factors. Simultaneously, the model reveals that group behavior does not universally drive individual vaccination; instead, it may lead to a persistent increase in susceptible individuals, thereby amplifying the risk of epidemic outbreaks. These findings hold significant practical implications for safeguarding public health and formulating vaccine policies.