SARS-CoV-2 Quarantine Mandated by Contact Tracing: Burden and Infection Rate Among Close Contacts in Zurich, Switzerland, 2020-2021

Hélène Eloise Aschmann; Anja Domenghino; Ruedi Jung; Tala Ballouz; Dominik Menges; Jan Fehr; Milo Alan Puhan

doi:10.3389/ijph.2024.1606221

SARS-CoV-2 Quarantine Mandated by Contact Tracing: Burden and Infection Rate Among Close Contacts in Zurich, Switzerland, 2020-2021

Int J Public Health. 2024 Sep 24:69:1606221. doi: 10.3389/ijph.2024.1606221. eCollection 2024.

Authors

Hélène Eloise Aschmann^{1

2

3}, Anja Domenghino^{3

4}, Ruedi Jung³, Tala Ballouz³, Dominik Menges³, Jan Fehr³, Milo Alan Puhan³

Affiliations

¹ Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, CA, United States.
² Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, United States.
³ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
⁴ Department of Visceral and Transplantation Surgery, University Hospital Zurich, Zurich, Switzerland.

Abstract

Objectives: Before vaccines and effective treatments were available, quarantine of close contacts was important to limit the spread of SARS-CoV-2. To evaluate potential benefits and harms of quarantine, we aimed to estimate infection rates and describe experiences and mental health among persons in mandated quarantine during the early SARS-CoV-2 pandemic.

Methods: We invited adults in mandated quarantine after an exposure to SARS-CoV-2 identified through contact tracing of the Canton of Zurich, Switzerland, between August 2020 and January 2021. Participants completed two questionnaires and received up to two SARS-CoV-2 polymerase chain reaction tests, during and at the end of quarantine.

Results: Among 395 participants, quarantine duration ranged from 2 to 20 days. By day 11 since the last contact, 11.1% [95% CI 8.4%-14.7%] were infected with SARS-CoV-2. The proportion of participants with symptoms of depression doubled from 9.3% before quarantine to 18.9% during quarantine, and 12.1% reported quarantine was very or extremely difficult.

Conclusion: Although quarantine was only moderately burdensome for most participants, some experienced significant difficulties and burden. Policymakers need to balance infection control with potential harms placed on individuals.

Keywords: COVID-19; SARS-CoV-2; burden; close contact; mental health; quarantine; secondary attack rate.

MeSH terms

Adolescent
Adult
Aged
COVID-19* / epidemiology
COVID-19* / prevention & control
Contact Tracing*
Depression / epidemiology
Female
Humans
Male
Middle Aged
Quarantine*
SARS-CoV-2*
Surveys and Questionnaires
Switzerland / epidemiology
Young Adult

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. The ZSAC study was funded through the Health Directorate of the Canton of Zurich and the Pandemic Fund of the University of Zurich. ZSAC was also part of the Corona Immunitas research program, coordinated by the Swiss School of Public Health (SSPH+) and funded through SSPH+ fundraising, including funding by the Swiss Federal Office of Public Health, the Cantons of Switzerland (Basel, Vaud, and Zurich), private funders (ethical guidelines for funding stated by SSPH+ were respected) and institutional funds of the participating universities. HA was also supported by a Swiss National Science Foundation Early Postdoc. Mobility Fellowship (191414) and a Postdoc. Mobility Fellowship (214129). TB received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 801076, through the SSPH+ Global PhD Fellowship Program in Public Health Sciences (GlobalP3HS) of the Swiss School of Public Health. Study funders had no role in the study design, data collection, analysis, interpretation, or writing of this report.