title: Spontaneous behavioural changes in response to epidemics.
abstract: We study how spontaneous reduction in the number of contacts could develop, as a defensive response, during an epidemic and affect the course of infection events. A model is proposed which couples an SIR model with selection of behaviours driven by imitation dynamics. Therefore, infection transmission and population behaviour become dynamical variables that influence each other. In particular, time scales of behavioural changes and epidemic transmission can be different. We provide a full qualitative characterization of the solutions when the dynamics of behavioural changes is either much faster or much slower than that of epidemic transmission. The model accounts for multiple outbreaks occurring within the same epidemic episode. Moreover, the model can explain "asymmetric waves", i.e., infection waves whose rising and decaying phases differ in slope. Finally, we prove that introduction of behavioural dynamics results in the reduction of the final attack rate.
authors.affiliation: Fondazione Bruno Kessler, Trento, Italy. poletti@fbk.eu
authors.forename: Piero
authors.initials: P
authors.lastname: Poletti
authors.forename: Bruno
authors.initials: B
authors.lastname: Caprile
authors.forename: Marco
authors.initials: M
authors.lastname: Ajelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Pugliese
authors.forename: Stefano
authors.initials: S
authors.lastname: Merler
mesh_terms: D003141:Communicable Diseases / Q000453:epidemiology* / Q000523:psychology* / Q000635:transmission; D058872:Epidemics; D015438:Health Behavior; D006801:Humans; D008954:Models, Biological; D008960:Models, Psychological; D011157:Population Dynamics