Interacting epidemics and coinfection on contact networks

TL;DR

This paper presents an exact mathematical model for two interacting diseases spreading on contact networks, revealing complex epidemic behaviors and control strategies involving coinfection dynamics.

Contribution

It introduces a novel exact solution for the sizes and phase diagram of two interacting epidemics on contact networks, accounting for dependency between diseases.

Findings

Exact outbreak sizes for both diseases in large populations

Complex phase diagram illustrating epidemic regimes

Control strategies targeting coinfection pathways

Abstract

The spread of certain diseases can be promoted, in some cases substantially, by prior infection with another disease. One example is that of HIV, whose immunosuppressant effects significantly increase the chances of infection with other pathogens. Such coinfection processes, when combined with nontrivial structure in the contact networks over which diseases spread, can lead to complex patterns of epidemiological behavior. Here we consider a mathematical model of two diseases spreading through a single population, where infection with one disease is dependent on prior infection with the other. We solve exactly for the sizes of the outbreaks of both diseases in the limit of large population size, along with the complete phase diagram of the system. Among other things, we use our model to demonstrate how diseases can be controlled not only by reducing the rate of their spread, but also by reducing the spread of other infections upon which they depend.