In this chapter, a modeling framework that explicitly accounts for human adaptations induced by risk perception in the epidemic dynamics is proposed. The diffusion of different behaviors is modeled according to a game theoretical approach and coupled with classic disease transmission models. The developed framework is used to assess the impact of human spontaneous behavioral changes on the natural history of vaccination programs and to investigate how a spontaneous defensive response enacted by susceptible individuals during an epidemic outbreak can affect the course of infection events. The complex interplay between behavioral changes and the epidemic transmission is investigated through the theoretical analysis of the resulting coupled dynamics and highlighted through some illustrative examples based on influenza- and measles-like infections. Our results suggest that human behavioral responses to the risk of infection can either positively or negatively impact the spread of epidemics.