Dynamics of beneficial epidemics

TL;DR

This paper explores how beneficial epidemics, such as advantageous viruses or innovations, spread faster and differently than harmful ones across biological and social systems using three theoretical models.

Contribution

It introduces three models showing that beneficial contagions spread superexponentially through populations, highlighting differences from detrimental epidemics.

Findings

Beneficial genetic elements spread superexponentially due to horizontal transmission.

Increased connectivity accelerates beneficial social contagions.

Preferences for global infection spread accelerate, while local preferences can halt epidemics.

Abstract

Pathogens can spread epidemically through populations. Beneficial contagions, such as viruses that enhance host survival or technological innovations that improve quality of life, also have the potential to spread epidemically. How do the dynamics of beneficial biological and social epidemics differ from those of detrimental epidemics? We investigate this question using three theoretical approaches. First, in the context of population genetics, we show that a horizontally-transmissible element that increases fitness, such as viral DNA, spreads superexponentially through a population, more quickly than a beneficial mutation. Second, in the context of behavioral epidemiology, we show that infections that cause increased connectivity lead to superexponential fixation in the population. Third, in the context of dynamic social networks, we find that preferences for increased global infection accelerate spread and produce superexponential fixation, but preferences for local assortativity halt epidemics by disconnecting the infected from the susceptible. We conclude that the dynamics of beneficial biological and social epidemics are characterized by the rapid spread of beneficial elements, which is facilitated in biological systems by horizontal transmission and in social systems by active spreading behavior of infected individuals.