Dynamics of COVID-19 based on spontaneous individual behaviors of vaccination

As the COVID-19 vaccine becomes widely available, human self-protection awareness is gradually weakening. However, the epidemic still continue to erupt repeatedly in various areas. Therefore, it is necessary to reveal the relationship between vaccination and individual spontaneous behaviors and their impact on the epidemic. Based on an SVEIR epidemic dynamical model, a novel imitation dynamics model is established by integrating the dynamic changes of individual spontaneous behaviors before and after vaccination. Unvaccinated people are more likely to choose long-term individual spontaneous behavior change strategies to reduce the risk of infection. While the vaccinated individuals are more likely to choose multiple, short-term strategies of individual spontaneous behavior changes. In the case of low vaccine protective efficacy, the changes of individual spontaneous behavior will drive several small-scale outbreaks at the same time. Besides, when the value of R₀ is 4.5 and vaccination rate is 0.45, keeping the vaccine protection efficacy above 76.3% can not only complement the epidemic recurrence caused by behavioral changes, but also effectively reduce the epidemic peak and therefore quickly control the epidemic. Our results reveal the underlying mechanisms between vaccination, vaccine protection efficacy, individual spontaneous behaviors of the two groups of people and the COVID-19 epidemic. Vaccination and its protective efficacy effectively have a reciprocal effect with individual behavior changes, so as to control the epidemic quickly and effectively.