Coupling between risk and cautious behavior affect epidemic morbidity, mortality and dynamics

TL;DR

This paper extends epidemic models to include the correlation between individual behavior and risk, revealing that positive correlation reduces morbidity and mortality, and influences responses to outbreaks and vaccination strategies.

Contribution

It introduces a model accounting for behavior-risk correlation, showing its impact on epidemic outcomes and response strategies, which was not addressed in prior models.

Findings

Positive correlation reduces morbidity and mortality.

Caution response influences lockdown effectiveness.

Vaccinated individuals' behavior affects herd immunity threshold.

Abstract

Models for epidemic spread typically account for variable risk factors but do not account for the correlation between behavior and risk. Here we extend these models to account for such correlations. We find that a positive correlation between behavior and risk, i.e., voluntary risk aversion by individuals at high risk and risk-taking behavior by individuals at low risk, leads to a linear reduction in morbidity and mortality and load on healthcare services compared to the uncorrelated case. We show that increasing caution in response to news from countries with a preceding outbreak leads to a more graded response to a lock-down. We also show that if vaccinated individuals are less cautious an increase in herd immunity threshold ensues.