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Airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Hospitals : Effects of Aerosol-Generating Procedures, HEPA-Filtration Units, Patient Viral Load, and Physical Distance

Thuresson, Sara LU ; Fraenkel, Carl Johan LU ; Sasinovich, Sviataslau LU ; Soldemyr, Jonathan LU ; Widell, Anders LU ; Medstrand, Patrik LU orcid ; Alsved, Malin LU orcid and Löndahl, Jakob LU orcid (2022) In Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 75(1). p.89-96
Abstract

BACKGROUND: Transmission of coronavirus disease 2019 (COVID-19) can occur through inhalation of fine droplets or aerosols containing infectious virus. The objective of this study was to identify situations, patient characteristics, environmental parameters, and aerosol-generating procedures (AGPs) associated with airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus.

METHODS: Air samples were collected near hospitalized COVID-19 patients and analyzed by RT-qPCR. Results were related to distance to the patient, most recent patient diagnostic PCR cycle threshold (Ct) value, room ventilation, and ongoing potential AGPs.

RESULTS: In total, 310 air samples were collected; of these, 26 (8%) were positive for... (More)

BACKGROUND: Transmission of coronavirus disease 2019 (COVID-19) can occur through inhalation of fine droplets or aerosols containing infectious virus. The objective of this study was to identify situations, patient characteristics, environmental parameters, and aerosol-generating procedures (AGPs) associated with airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus.

METHODS: Air samples were collected near hospitalized COVID-19 patients and analyzed by RT-qPCR. Results were related to distance to the patient, most recent patient diagnostic PCR cycle threshold (Ct) value, room ventilation, and ongoing potential AGPs.

RESULTS: In total, 310 air samples were collected; of these, 26 (8%) were positive for SARS-CoV-2. Of the 231 samples from patient rooms, 22 (10%) were positive for SARS-CoV-2. Positive air samples were associated with a low patient Ct value (OR, 5.0 for Ct <25 vs >25; P = .01; 95% CI: 1.18-29.5) and a shorter physical distance to the patient (OR, 2.0 for every meter closer to the patient; P = .05; 95% CI: 1.0-3.8). A mobile HEPA-filtration unit in the room decreased the proportion of positive samples (OR, .3; P = .02; 95% CI: .12-.98). No association was observed between SARS-CoV-2-positive air samples and mechanical ventilation, high-flow nasal cannula, nebulizer treatment, or noninvasive ventilation. An association was found with positive expiratory pressure training (P < .01) and a trend towards an association for airway manipulation, including bronchoscopies and in- and extubations.

CONCLUSIONS: Our results show that major risk factors for airborne SARS-CoV-2 include short physical distance, high patient viral load, and poor room ventilation. AGPs, as traditionally defined, seem to be of secondary importance.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
COVID-19, Hospitals, Humans, Physical Distancing, Respiratory Aerosols and Droplets, SARS-CoV-2, Viral Load
in
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
volume
75
issue
1
pages
89 - 96
publisher
Oxford University Press
external identifiers
  • pmid:35226740
  • scopus:85144521125
ISSN
1537-6591
DOI
10.1093/cid/ciac161
language
English
LU publication?
yes
id
7e08ccaa-aab7-4d27-915c-2e5f0c2af23b
date added to LUP
2022-10-17 14:48:53
date last changed
2024-04-18 15:49:00
@article{7e08ccaa-aab7-4d27-915c-2e5f0c2af23b,
  abstract     = {{<p>BACKGROUND: Transmission of coronavirus disease 2019 (COVID-19) can occur through inhalation of fine droplets or aerosols containing infectious virus. The objective of this study was to identify situations, patient characteristics, environmental parameters, and aerosol-generating procedures (AGPs) associated with airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus.</p><p>METHODS: Air samples were collected near hospitalized COVID-19 patients and analyzed by RT-qPCR. Results were related to distance to the patient, most recent patient diagnostic PCR cycle threshold (Ct) value, room ventilation, and ongoing potential AGPs.</p><p>RESULTS: In total, 310 air samples were collected; of these, 26 (8%) were positive for SARS-CoV-2. Of the 231 samples from patient rooms, 22 (10%) were positive for SARS-CoV-2. Positive air samples were associated with a low patient Ct value (OR, 5.0 for Ct &lt;25 vs &gt;25; P = .01; 95% CI: 1.18-29.5) and a shorter physical distance to the patient (OR, 2.0 for every meter closer to the patient; P = .05; 95% CI: 1.0-3.8). A mobile HEPA-filtration unit in the room decreased the proportion of positive samples (OR, .3; P = .02; 95% CI: .12-.98). No association was observed between SARS-CoV-2-positive air samples and mechanical ventilation, high-flow nasal cannula, nebulizer treatment, or noninvasive ventilation. An association was found with positive expiratory pressure training (P &lt; .01) and a trend towards an association for airway manipulation, including bronchoscopies and in- and extubations.</p><p>CONCLUSIONS: Our results show that major risk factors for airborne SARS-CoV-2 include short physical distance, high patient viral load, and poor room ventilation. AGPs, as traditionally defined, seem to be of secondary importance.</p>}},
  author       = {{Thuresson, Sara and Fraenkel, Carl Johan and Sasinovich, Sviataslau and Soldemyr, Jonathan and Widell, Anders and Medstrand, Patrik and Alsved, Malin and Löndahl, Jakob}},
  issn         = {{1537-6591}},
  keywords     = {{COVID-19; Hospitals; Humans; Physical Distancing; Respiratory Aerosols and Droplets; SARS-CoV-2; Viral Load}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{1}},
  pages        = {{89--96}},
  publisher    = {{Oxford University Press}},
  series       = {{Clinical infectious diseases : an official publication of the Infectious Diseases Society of America}},
  title        = {{Airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Hospitals : Effects of Aerosol-Generating Procedures, HEPA-Filtration Units, Patient Viral Load, and Physical Distance}},
  url          = {{http://dx.doi.org/10.1093/cid/ciac161}},
  doi          = {{10.1093/cid/ciac161}},
  volume       = {{75}},
  year         = {{2022}},
}