Effects of fear on transmission dynamics of infectious diseases

Abstract

An epidemiological model that incorporates individual adoption of protective behaviours due to fear of contracting an infectious disease is presented. These adaptive behaviours are assumed to lower an individual's risk of infection. The dynamics of this model are analyzed and the effects of fear on important public health metrics such as outbreak length, final size, and peak prevalence are investigated. It is concluded that the coupled dynamics of fear- and disease-spread are rich and can lead to counter-intuitive effects on the public health metrics considered. In particular, it is not always the case that more effective protective behaviours lead to the most favourable population-level outcomes; intermediate levels of effectiveness are optimal in some cases. This result depends on when fearful individuals become infected with respect to the main outbreak that is mostly driven by the infection of fully susceptible individuals.