Understanding the Oscillations of Epidemic Due to Vaccine Hesitancy

Vaccine hesitancy threatens the possibility of ending the COVID-19 pandemic through mass vaccination. We use an SIS model with a game theory model for vaccination, which we call an SIV model, to study how vaccine hesitancy impact epidemic dynamics. The system shows three asymptotic behaviors: total rejection, full acceptance, and oscillation. With increasing fear of infection, stable endemic states become periodic oscillations. Our results suggest that managing fear of infection relative to vaccination is key to successful mass vaccinations.