• English
    • español
    • português (Brasil)
  • English 
    • English
    • español
    • português (Brasil)
  • Login
View Item 
  •   COVID-19
  • Resources in English
  • Technical documents and research evidence on COVID-19
  • View Item
  •   COVID-19
  • Resources in English
  • Technical documents and research evidence on COVID-19
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Assessing the impact of non-pharmaceutical interventions on SARS-CoV-2 transmission in Switzerland

 
Thumbnail
Date
2020-05-08
Author
Lemaitre, Joseph Chadi et al.
Metadata
Show full item record
Abstract
Following the rapid dissemination of COVID-19 cases in Switzerland, large-scale non- pharmaceutical interventions (NPIs) were implemented by the cantons and the federal government between February 28 and March 20. Estimates of the impact of these interventions on SARS-CoV-2 transmission are critical for decision making in this and future outbreaks. We here aim to assess the impact of these NPIs on disease transmission by estimating changes in the basic reproduction number (R0) at national and cantonal levels in relation to the timing of these NPIs. We estimate the time- varying R0 nationally and in twelve cantons by fitting a stochastic transmission model explicitly simulating within hospital dynamics. We use individual-level data of >1,000 hospitalized patients in Switzerland and public daily reports of hospitalizations and deaths. We estimate the national R0 was 3.15 (95% CI: 2.13-3.76) at the start of the epidemic. Starting from around March 6, we find a strong reduction in R0 with an 85% median decrease (95% quantile range, QR: 83%-90%) to a value of 0.44 (95% QR: 0.27-0.65) in the period of March 29-April 5. At the cantonal-level R0 decreased over the course of the epidemic between 71% and 94%. We found that reductions in R0 were synchronous with changes in mobility patterns as estimated through smartphone activity, which started before the official implementation of NPIs. We found that most of the reduction of transmission is due to behavioural changes as opposed to natural immunity, the latter accounting for only about 3% of the total reduction in effective transmission. As Switzerland considers relaxing some of the restrictions of social mixing, current estimates of R0 well below one are promising. However most of inferred transmission reduction was due to behaviour change (<3% due to natural immunity buildup), with an estimated 97% (95% QR: 96.6%-97.2%) of the Swiss population still susceptible to SARS-CoV-2 as of April 24. These results warrant a cautious relaxation of social distance practices and close monitoring of changes in both the basic and effective reproduction numbers.
URI
https://doi.org/10.1101/2020.05.04.20090639
Collections
  • Technical documents and research evidence on COVID-19

Browse

AllCommunities & CollectionsBy Issue DateAuthorsTitlesCategorySubjectsThis CollectionBy Issue DateAuthorsTitlesCategorySubjects

My Account

LoginRegister

Pan American Health Organization
World Health Organization. Regional Office for the Americas
525 Twenty-third Street, N.W., Washington, D.C. 20037, United States of America

Content Disclaimer (Important notes about the material)

Links

  • WHO International Clinical Trial Registry Platform (ICTRP)
  • WHO Coronavirus disease R&D Blueprint
  • WHO Database of Publications on Coronavirus Disease
  • PAHO Coronavirus Disease
  • PAHO/BIREME Windows of Knowledge COVID-19
  • Evidence aid Coronavirus (COVID-19) resources

  • PAHO Digital Library (IRIS PAHO)
  • Virtual Health Library (VHL)
  • Global Index Medicus (GIM)