title: A susceptible-infected epidemic model with voluntary vaccinations.
abstract: An susceptible-infected epidemic model with endogenous behavioral changes is presented to analyze the impact of a prophylactic vaccine on disease prevalence. It is shown that, with voluntary vaccination, whether an endemic equilibrium exists or not does not depend on vaccine efficacy or the distribution of agent-types. Although an endemic equilibrium is unique in the absence of a vaccine, the availability of a vaccine can lead to multiple endemic equilibria that differ in disease prevalence and vaccine coverage. Depending on the distribution of agent-types, the introduction of a vaccine or, if one is available, a subsidy for vaccination can increase disease prevalence by inducing more risky behavior.
authors.affiliation: Department of Economics, Wake Forest University, Box 7505, Winston-Salem, NC 27109-7505, USA. chenfh@wfu.edu
authors.forename: Frederick H
authors.initials: FH
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D003140:Communicable Disease Control; D004196:Disease Outbreaks; D015658:HIV Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control; D006291:Health Policy; D006801:Humans; D008954:Models, Biological; D040242:Risk Reduction Behavior; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D014611:Vaccination / Q000379:methods*