Sudden transitions in coupled opinion and epidemic dynamics with vaccination

TL;DR

This paper models the interplay between opinion dynamics and epidemic spreading with vaccination, revealing how risk perception influences vaccination behavior and can lead to sudden phase transitions in disease prevalence.

Contribution

It introduces a coupled opinion-epidemic model with continuous opinions and demonstrates the emergence of first-order phase transitions and counterintuitive effects of vaccination strategies.

Findings

First-order phase transition observed in epidemic dynamics.

Initial pro-vaccine opinion can reduce short-term outbreaks.

More effective vaccines may decrease long-term coverage.

Abstract

This work consists of an epidemic model with vaccination coupled with an opinion dynamics. Our objective was to study how disease risk perception can influence opinions about vaccination and therefore the spreading of the disease. Differently from previous works we have considered continuous opinions. The epidemic spreading is governed by a SIS-like model with an extra vaccinated state. In our model individuals vaccinate with a probability proportional to their opinions. The opinions change due to peer influence in pairwise interactions. The epidemic feedback to the opinion dynamics acts as an external field increasing the vaccination probability. We performed Monte Carlo simulations in fully-connected populations. Interestingly we observed the emergence of a first-order phase transition, besides the usual active-absorbing phase transition presented in the SIS model. Our simulations also show that with a certain combination of parameters, an increment in the initial fraction of the population that is pro-vaccine has a twofold effect: it can lead to smaller epidemic outbreaks in the short term, but it also contributes to the survival of the chain of infections in the long term. Our results also suggest that it is possible that more effective vaccines can decrease the long-term vaccine coverage. This is a counterintuitive outcome, but it is in line with empirical observations that vaccines can become a victim of their own success.