Swiss Medical Weekly (Dec 2020)

Early evidence of effectiveness of digital contact tracing for SARS-CoV-2 in Switzerland

  • Marcel Salathé,
  • Christian L. Althaus,
  • Nanina Anderegg,
  • Daniele Antonioli,
  • Tala Ballouz,
  • Edouard Bugnion,
  • Srdjan Čapkun,
  • Dennis Jackson,
  • Sang-Il Kim,
  • James R. Larus,
  • Nicola Low,
  • Wouter Lueks,
  • Dominik Menges,
  • Cédric Moullet,
  • Mathias Payer,
  • Julien Riou,
  • Theresa Stadler,
  • Carmela Troncoso,
  • Effy Vayena,
  • Viktor von Wyl

DOI
https://doi.org/10.4414/smw.2020.20457
Journal volume & issue
Vol. 150, no. 5153

Abstract

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In the wake of the pandemic of coronavirus disease 2019 (COVID-19), contact tracing has become a key element of strategies to control the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Given the rapid and intense spread of SARS-CoV-2, digital contact tracing has emerged as a potential complementary tool to support containment and mitigation efforts. Early modelling studies highlighted the potential of digital contact tracing to break transmission chains, and Google and Apple subsequently developed the Exposure Notification (EN) framework, making it available to the vast majority of smartphones. A growing number of governments have launched or announced EN-based contact tracing apps, but their effectiveness remains unknown. Here, we report early findings of the digital contact tracing app deployment in Switzerland. We demonstrate proof-of-principle that digital contact tracing reaches exposed contacts, who then test positive for SARS-CoV-2. This indicates that digital contact tracing is an effective complementary tool for controlling the spread of SARS-CoV-2. Continued technical improvement and international compatibility can further increase the efficacy, particularly also across country borders.

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