Viral load of SARS-CoV-2 in droplets and bioaerosols directly captured during breathing, speaking and coughing.
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Authors
Johnson, Tyler J
Nishida, Robert T
Lin, Yi-Chan James
Watson, Kimberley A
Smith, Stephanie W
Conly, John M
Evans, David H
Olfert, Jason S
Publication Date
2022-03-03Journal Title
Sci Rep
ISSN
2045-2322
Publisher
Springer Science and Business Media LLC
Volume
12
Issue
1
Language
eng
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Johnson, T. J., Nishida, R. T., Sonpar, A. P., Lin, Y. J., Watson, K. A., Smith, S. W., Conly, J. M., et al. (2022). Viral load of SARS-CoV-2 in droplets and bioaerosols directly captured during breathing, speaking and coughing.. Sci Rep, 12 (1) https://doi.org/10.1038/s41598-022-07301-5
Abstract
Determining the viral load and infectivity of SARS-CoV-2 in macroscopic respiratory droplets, bioaerosols, and other bodily fluids and secretions is important for identifying transmission modes, assessing risks and informing public health guidelines. Here we show that viral load of SARS-CoV-2 Ribonucleic Acid (RNA) in participants' naso-pharyngeal (NP) swabs positively correlated with RNA viral load they emitted in both droplets >10 [Formula: see text] and bioaerosols <10 [Formula: see text] directly captured during the combined expiratory activities of breathing, speaking and coughing using a standardized protocol, although the NP swabs had [Formula: see text] 10[Formula: see text] more RNA on average. By identifying highly-infectious individuals (maximum of 18,000 PFU/mL in NP), we retrieved higher numbers of SARS-CoV-2 RNA gene copies in bioaerosol samples (maximum of 4.8[Formula: see text] gene copies/mL and minimum cycle threshold of 26.2) relative to other studies. However, all attempts to identify infectious virus in size-segregated droplets and bioaerosols were negative by plaque assay (0 of 58). This outcome is partly attributed to the insufficient amount of viral material in each sample (as indicated by SARS-CoV-2 gene copies) or may indicate no infectious virus was present in such samples, although other possible factors are identified.
Keywords
Humans, Cough, Aerosols, Viral Load, Speech, Respiration, SARS-CoV-2
Sponsorship
Natural Sciences and Engineering Research Council of Canada (Postdoctoral Fellowships Program)
World Health Organization (Research grant for the Infection Prevention and Control (IPC) Pillar.)
Identifiers
35241703, PMC8894466
External DOI: https://doi.org/10.1038/s41598-022-07301-5
This record's URL: https://www.repository.cam.ac.uk/handle/1810/335722
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