Goyal, S. and Vigier, A.
Interaction, Protection and Epidemics
WP Number: 1409
Abstract: Individuals respond to the risk of infectious diseases by restricting interaction and by investing in
protection. We develop a model that examines the trade-off between these two actions and the
consequences for disease prevalence.
There exists a unique equilibrium: individuals who invest in protection choose to interact more
relative to those who do not invest in protection. Changes in the contagiousness of the disease have nonmonotonic
effects: as a result interaction initially falls and then rises, while disease prevalence too may
initial increase and then decline.
We then consider a society with two communities that differ in their returns from interaction -
High and Low. Individuals in isolated communities exhibit different behavior: the High community has a
higher rate of protection and interaction and a lower rate of infection. Integration amplifies these
differences.
Keywords: Epidemics, Social interaction, Vaccination
JEL Codes: I12 D85
Author links: Sanjeev Goyal
PDF: wp1409.pdf 
Open Access Link: 10.17863/CAM.5658
Theme: networks
Published Version of Paper: Interaction, Protection and Epidemics, Goyal, S, and Vigier, A., Journal of Public Economics (2015)