title: Bistability of Evolutionary Stable Vaccination Strategies in the Reinfection SIRI Model.
abstract: We use the reinfection SIRI epidemiological model to analyze the impact of education programs and vaccine scares on individuals decisions to vaccinate or not. The presence of the reinfection provokes the novelty of the existence of three Nash equilibria for the same level of the morbidity relative risk instead of a single Nash equilibrium as occurs in the SIR model studied by Bauch and Earn (PNAS 101:13391-13394, 2004). The existence of three Nash equilibria, with two of them being evolutionary stable, introduces two scenarios with relevant and opposite features for the same level of the morbidity relative risk: the low-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a low probability; and the high-vaccination scenario corresponding to the evolutionary stable vaccination strategy, where individuals will vaccinate with a high probability. We introduce the evolutionary vaccination dynamics for the SIRI model and we prove that it is bistable. The bistability of the evolutionary dynamics indicates that the damage provoked by false scares on the vaccination perceived morbidity risks can be much higher and much more persistent than in the SIR model. Furthermore, the vaccination education programs to be efficient they need to implement a mechanism to suddenly increase the vaccination coverage level.
authors.affiliation: LIAAD-INESC TEC, R Dr Roberto Frias, 4200-465, Porto, Portugal. jmmartins@ipleiria.pt.|School of Technology and Management, Polytechnic Institute of Leiria, Campus 2, Morro do Lena - Alto do Vieiro, 2411-901, Leiria, Portugal. jmmartins@ipleiria.pt.
authors.forename: José
authors.identifier: http://orcid.org/0000-0002-0556-7861
authors.initials: J
authors.lastname: Martins
authors.affiliation: LIAAD-INESC TEC, R Dr Roberto Frias, 4200-465, Porto, Portugal.|Faculty of Sciences, University of Porto, R Campo Alegre, 4169-007, Porto, Portugal.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pinto
mesh_terms: D005075:Biological Evolution; D003657:Decision Making; D006801:Humans; D008962:Models, Theoretical; D014611:Vaccination
keywords: ESS; Nash equilibrium; Reinfection; SIRI model; Vaccination; Vaccination dynamics