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PreprintCited by 58COVID-19 epidemiological studiesCOVID-19 Prevention and ImpactSARS-CoV-2 and COVID-19 Research

Effectiveness of Localized Lockdowns in the COVID-19 Pandemic

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Li, Yige, Undurraga, Eduardo A., Zubizarreta, José R.·2020·American Journal of Epidemiology
DOI 10.1101/2020.08.25.20182071PMC PMC8807239

Preprint — published as 10.1093/aje/kwac008

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Abstract

Non-pharmaceutical interventions, such as social distancing and lockdowns, have been essential to control the COVID-19 pandemic. In particular, localized lockdowns in small geographic areas have become an important policy intervention to prevent viral spread in cases of resurgence. These localized lockdowns can result in lower social and economic costs compared to larger-scale suppression strategies. Using an integrated dataset from Chile (March 3 through June 15, 2020) and a novel synthetic control approach, in this paper we estimate the effect of localized lockdowns, disentangling its direct and indirect causal effects on SARS-CoV-2 transmission. Our results show that the effects of localized lockdowns are strongly modulated by their duration and are influenced by indirect effects from neighboring geographic areas. Our estimates suggest that extending localized lockdowns can slow down the pandemic; however, localized lockdowns on their own are insufficient to control pandemic growth in the presence of indirect effects from contiguous neighboring areas that do not have lockdowns. These results provide critical empirical evidence about the effectiveness of localized lockdowns in interconnected geographic areas.

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  49. [1]1. Incidence of COVID-19 cases in Chile, March 1 to July 15, 2020. The majority (66%) of cases were reported in Greater Santiago (solid line). <!-- image --> is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint medRxiv preprint doi: https://doi.org/10.1101/2020.08.25.20182071; this version posted November 17, 2021. The copyright holder for this [It is made available under a CC-BY 4.0 International license .](http://creativecommons.org/licenses/by/4.0/) Figure
  50. [2]2. Lockdowns and instantaneous reproduction number. (A) Municipality-level lockdowns in Greater Santiago on March 31, April 15, April 30, and May 15, 2020. (B) Variation of the instantaneous reproduction number ( 𝑅𝑡 ) and the proportion of the population under lockdown in Greater Santiago over time. <!-- image --> is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint medRxiv preprint doi: https://doi.org/10.1101/2020.08.25.20182071; this version posted November 17, 2021. The copyright holder for this [It is made available under a CC-BY 4.0 International license .](http://creativecommons.org/licenses/by/4.0/) Figure
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  53. [5]5. Estimated instantaneous reproduction number 𝑹𝒕 and incidence It under different lockdown interventions by municipality. In (A), the grey solid and blue dashed lines show the proportion of the population in the surrounding municipalities under lockdown, respectively for the observed and the intervened 𝑃𝑡 ( 𝑃𝑡 𝑜𝑏𝑠. and 𝑃𝑡 𝑖𝑛𝑡. ). In (A, B), the lighter shade of blue extends the duration of the lockdown. The solid black lines show the reproduction number 𝑅𝑡 (A) and daily incidence 𝐼 𝑡 (B), and the dashed lines show the predicted 𝑅𝑡 and case incidence 𝐼 𝑡 for the extended lockdown. The direct and total effects of the extended lockdown are the difference between the solid black line and dashed line with grey ( 𝑅𝑡 𝑑𝑖𝑟. , 𝐼 𝑡 dir. ) and blue ( 𝑅𝑡 𝑡𝑜𝑡. , 𝐼 𝑡 tot. ) bands, respectively. The bands around the curves indicate 95% confidence intervals (additional results in the Supplementary Material). is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint medRxiv preprint doi: https://doi.org/10.1101/2020.08.25.20182071; this version posted November 17, 2021. The copyright holder for this [It is made available under a CC-BY 4.0 International license .](http://creativecommons.org/licenses/by/4.0/) Figure
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  55. [7]7. Effectiveness of lockdowns for different target areas. (A) In blue, municipalities of Greater Santiago under lockdown at different points in time; outlined in red (Ñuñoa), orange (cluster of six municipalities), and green (Greater Santiago), lockdown target areas of increasing size. (B-D) Estimated instantaneous reproduction number <!-- image --> is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint medRxiv preprint doi: https://doi.org/10.1101/2020.08.25.20182071; this version posted November 17, 2021. The copyright holder for this [It is made available under a CC-BY 4.0 International license .](http://creativecommons.org/licenses/by/4.0/) 𝑅𝑡 , with changing proportions of the population under lockdown in each geographic area and its immediate neighboring areas. From top to bottom the figure shows the municipality of Ñuñoa, a cluster of six municipalities, and the city Greater Santiago. (B-C) Also show the predicted 𝑅𝑡 (dashed line) had the lockdowns in the geographic area and for its immediate neighbors been extended. We estimate that the epidemic would have continued to grow ( 𝑅𝑡 ≥ 1 ) even with the extended localized lockdowns. The epidemic kept growing until Greater Santiago was put under lockdown on May 15, 2020.

Authors
Li, Y., Undurraga, E. A., & Zubizarreta, J. R.
Affiliations
Harvard University (US)
Corresponding author
Zubizarreta, José R.
ORCID
Venue
American Journal of Epidemiology
Publisher
openRxiv
Published
2020-08-31
Volume
191
Issue
5
Pages
812-824
ISSN
0002-9262 (ISSN-L)
DOI
10.1101/2020.08.25.20182071
PMC
PMC8807239
OpenAlex
W4205667523
Cited by
58
References
59
Citations by year
2026: 4 · 2025: 7 · 2024: 12 · 2023: 15 · 2022: 11 · 2021: 7 · 2020: 2
FWCI
6.69
Type
journal article
Language
en
Open access
Locations
  • American Journal of Epidemiology (publishedVersion)
  • medRxiv (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Alfred P. Sloan Foundation (g-2018-10118)
  • Patient-Centered Outcomes Research Institute (ME‐2019C1‐16172)
  • University of Pennsylvania
  • Harvard University
  • University of Oxford
  • Universidad de Chile
  • Pontificia Universidad Católica de Chile
  • Agencia Nacional de Investigación y Desarrollo (15110017, NCN17_081)
  • Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (15110017)
Topics
  • Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
  • Social Sciences › Sociology and Political Science › COVID-19 Prevention and Impact
  • Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
Keywords
COVID-19 pandemic, SARS-CoV-2 transmission, non-pharmaceutical interventions, social distancing, synthetic control method, lockdown duration, pandemic response, Chile
MeSH terms
Physical Distancing, COVID-19, SARS-CoV-2, Communicable Disease Control, Humans, Pandemics

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