Previously, we conducted a systematic review and analyzed the respiratory kinetics of SARS-CoV-2 (P. Z. Chen et al., 2021). How age, sex and COVID-19 severity interplay to influence the shedding dynamics of SARS-CoV-2, however, remains poorly understood.
We updated our systematic dataset, collected individual case characteristics and conducted stratified analyses of SARS-CoV-2 shedding dynamics in the upper (URT) and lower respiratory tract (LRT) across COVID-19 severity, sex and age groups (aged 0 to 17 years, 18 to 59 years, and 60 years or older).
The systematic dataset included 1,266 adults and 136 children with COVID-19. Our analyses indicated that high, persistent LRT shedding of SARS-CoV-2 characterized severe COVID-19 in adults. Severe cases tended to show slightly higher URT shedding post-symptom onset, but similar rates of viral clearance, when compared to nonsevere infections. After stratifying for disease severity, sex and age (including child vs. adult) were not predictive of respiratory shedding. The estimated accuracy for using LRT shedding as a prognostic indicator for COVID-19 severity was up to 81%, whereas it was up to 65% for URT shedding.
Virological factors, especially in the LRT, facilitate the pathogenesis of severe COVID-19. Disease severity, rather than sex or age, predict SARS-CoV-2 kinetics. LRT viral load may prognosticate COVID-19 severity in patients before the timing of deterioration, and should do so more accurately than URT viral load.
Natural Sciences and Engineering Research Council of Canada (NSERC) DiscoveryGrant, NSERC Senior Industrial Research Chair and the Toronto COVID-19 Action Fund.
The systematic dataset and model outputs from this study can be download from a public repository (https://zenodo.org/record/5209064). The code generated during this study is available at GitHub (https://github.com/paulzchen/sars2-shedding). The systematic review protocol was prospectively registered on PROSPERO (registration number, CRD42020204637).
- Paul Z Chen
- David N Fisman
- Frank X Gu
- Frank X Gu
The funders had no role in study design, collection or interpretation of the data, preparation of the manuscript, or the decision to submit the manuscript for publication.
- Jos W Van der Meer, Radboud University Medical Centre, Netherlands
- Received: May 28, 2021
- Accepted: August 17, 2021
- Accepted Manuscript published: August 20, 2021 (version 1)
© 2021, Chen et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.