Two-pathogen model with competition on clustered networks

TL;DR

This paper investigates how clustering in social networks influences the spread and coexistence of sequential pathogen strains, revealing that clustering generally facilitates the second wave of an epidemic.

Contribution

It introduces a generating function framework to analyze the effects of clustering on pathogen spread and derives conditions for strain coexistence thresholds.

Findings

Clustering reduces the coexistence threshold in Poisson networks.

Clustering increases the outbreak size of the second strain.

Clustering facilitates the second wave of epidemics in clustered networks.

Abstract

Networks provide a mathematically rich framework to represent social contacts sufficient for the transmission of disease. Social networks are often highly clustered and fail to be locally tree-like. In this paper, we study the effects of clustering on the spread of sequential strains of a pathogen using the generating function formulation under a complete cross-immunity coupling, deriving conditions for the threshold of coexistence of the second strain. We show that clustering reduces the coexistence threshold of the second strain and its outbreak size in Poisson networks, whilst exhibiting the opposite effects on uniform-degree models. We conclude that clustering within a population must increase the ability of the second wave of an epidemic to spread over a network. We apply our model to the study of multilayer clustered networks and observe the fracturing of the residual graph at two distinct transmissibilities.