Estimating the number of undetected COVID-19 cases among travellers from mainland China.
File(s)
Author(s)
Type
Journal Article
Abstract
Background: As of August 2021, every region of the world has been affected by the COVID-19 pandemic, with more than 196,000,000 cases worldwide.
Methods: We analysed COVID-19 cases among travellers from mainland China to different regions and countries, comparing the region- and country-specific rates of detected and confirmed cases per flight volume to estimate the relative sensitivity of surveillance in different regions and countries.
Results: Although travel restrictions from Wuhan City and other cities across China may have reduced the absolute number of travellers to and from China, we estimated that up to 70% (95% CI: 54% - 80%) of imported cases could remain undetected relative to the sensitivity of surveillance in Singapore. The percentage of undetected imported cases rises to 75% (95% CI 66% - 82%) when comparing to the surveillance sensitivity in multiple countries.
Conclusions: Our analysis shows that a large number of COVID-19 cases remain undetected across the world. These undetected cases potentially resulted in multiple chains of human-to-human transmission outside mainland China.
Methods: We analysed COVID-19 cases among travellers from mainland China to different regions and countries, comparing the region- and country-specific rates of detected and confirmed cases per flight volume to estimate the relative sensitivity of surveillance in different regions and countries.
Results: Although travel restrictions from Wuhan City and other cities across China may have reduced the absolute number of travellers to and from China, we estimated that up to 70% (95% CI: 54% - 80%) of imported cases could remain undetected relative to the sensitivity of surveillance in Singapore. The percentage of undetected imported cases rises to 75% (95% CI 66% - 82%) when comparing to the surveillance sensitivity in multiple countries.
Conclusions: Our analysis shows that a large number of COVID-19 cases remain undetected across the world. These undetected cases potentially resulted in multiple chains of human-to-human transmission outside mainland China.
Date Issued
2020-01
Date Acceptance
2020-01-01
Citation
Wellcome open research, 2020, 5, pp.143-143
ISSN
2398-502X
Start Page
143
End Page
143
Journal / Book Title
Wellcome open research
Volume
5
Copyright Statement
© 2021 Bhatia S et al. This is an open access article distributed under the terms of the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Sponsor
Medical Research Council (MRC)
Medical Research Council (MRC)
International Society for Infectious Diseases
Wellcome Trust
Identifier
https://wellcomeopenresearch.org/articles/5-143
Grant Number
MR/K010174/1B
MR/R015600/1
SBFF-2019-37324
213494/Z/18/Z
Publication Status
Published
Date Publish Online
2020-06-15