On limits of contact tracing in epidemic control

PLoS One. 2021 Aug 18;16(8):e0256180. doi: 10.1371/journal.pone.0256180. eCollection 2021.

Abstract

Contact tracing and quarantine are well established non-pharmaceutical epidemic control tools. The paper aims to clarify the impact of these measures in evolution of epidemic. The proposed deterministic model defines a simple rule on the reproduction number [Formula: see text] in terms of ratio of diagnosed cases and, quarantine and transmission parameters. The model is applied to the early stage of Covid19 crisis in Poland. We investigate 3 scenarios corresponding to different ratios of diagnosed cases. Our results show that, depending on the scenario, contact tracing prevented from 50% to over 90% of cases. The effects of quarantine are limited by fraction of undiagnosed cases. The key conclusion is that under realistic assumptions the epidemic can not be controlled without any social distancing measures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • COVID-19 / epidemiology*
  • COVID-19 / prevention & control
  • COVID-19 / transmission
  • Computer Simulation
  • Contact Tracing / methods
  • Contact Tracing / statistics & numerical data*
  • Epidemiological Models*
  • Humans
  • Physical Distancing
  • Poland / epidemiology
  • Quarantine / methods
  • Quarantine / statistics & numerical data*
  • SARS-CoV-2 / pathogenicity

Grants and funding

This study was supported by the Polish National Science Centre in the form of a grant awarded to P.M. (No2018/30/M/ST1/00340) and the National Institute of Public Health NIH Statutory Task awarded to M.R. (No. BE2021). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.