Emergence of protective behaviour under different risk perceptions to disease spreading

TL;DR

This paper investigates how different risk perceptions influence the emergence of protective behaviors during disease spread, revealing conditions under which risky individuals choose protection or rely on herd immunity.

Contribution

It introduces a coupled epidemic-behavior model distinguishing concerned and risky individuals, analyzing how their behaviors impact epidemic thresholds and herd immunity.

Findings

Protection strategies alter epidemic thresholds for both subpopulations

Risky individuals may or may not adopt protection depending on social dynamics

Concerned individuals can indirectly shield risky individuals through herd immunity

Abstract

The behaviour of individuals is a main actor in the control of the spread of a communicable disease and, in turn, the spread of an infectious disease can trigger behavioural changes in a population. Here, we study the emergence of the individuals protective behaviours in response to the spread of a disease by considering two different social attitudes within the same population: concerned and risky. Generally speaking, concerned individuals have a larger risk aversion than risky individuals. To study the emergence of protective behaviours, we couple, to the epidemic evolution of a susceptible-infected-susceptible model, a decision game based on the perceived risk of infection. Using this framework, we find the effect of the protection strategy on the epidemic threshold for each of the two subpopulations (concerned and risky), and study under which conditions risky individuals are persuaded to protect themselves or, on the contrary, can take advantage of a herd immunity by remaining healthy without protecting themselves, thanks to the shield provided by concerned individuals.