The effect of delay on contact tracing

TL;DR

This paper models how delays and randomness in contact tracing impact the control of infectious disease outbreaks, especially affecting the reproduction number and tracing effectiveness.

Contribution

It introduces a model incorporating tracing delays and analyzes how delay length and randomness influence disease spread control.

Findings

Randomness in tracing delay significantly affects outbreak dynamics.

Longer delays reduce the effectiveness of contact tracing.

Delay variability impacts the reproduction number.

Abstract

We consider a model for an infectious disease in the onset of an outbreak. We introduce contact tracing incorporating a tracing delay. The effect of randomness in the delay and the effect of the length of this delay in comparison to the infectious period of the disease respectively to a latency period on the effect of tracing, given e.g. by the change of the reproduction number, is analyzed. We focus particularly on the effect of randomness in the tracing delay.