Containing the spread of a contagion on a tree

TL;DR

This paper models infection spread on a tree and explores strategies for a tracer to effectively contain the contagion by stabilizing nodes based on various criteria.

Contribution

It introduces a simple infection model on trees and analyzes node stabilization policies to optimize containment efforts.

Findings

Prioritizing nodes by time can effectively slow infection spread.

Stabilization based on infectiousness reduces overall contagion.

Policy effectiveness varies with infection parameters.

Abstract

Contact tracing can be thought of as a race between two processes: an infection process and a tracing process. In this paper, we study a simple model of infection spreading on a tree, and a tracer who stabilizes one node at a time. We focus on the question, how should the tracer choose nodes to stabilize so as to prevent the infection from spreading further? We study simple policies, which prioritize nodes based on time, infectiousness, or probability of generating new contacts.