Surface and Air Contamination With Severe Acute Respiratory Syndrome Coronavirus 2 From Hospitalized Coronavirus Disease 2019 Patients in Toronto, Canada, March–May 2020
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Abstract
Background
We determined the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in air and on surfaces in rooms of patients hospitalized with coronavirus disease 2019 (COVID-19) and investigated patient characteristics associated with SARS-CoV-2 environmental contamination.
Methods
Nasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at 6 acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 ribonucleic acid (RNA), cultured to determine potential infectivity, and whole viral genomes were sequenced. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated.
Results
Severe acute respiratory syndrome coronavirus 2 RNA was detected from surfaces (125 of 474 samples; 42 of 78 patients) and air (3 of 146 samples; 3 of 45 patients); 17% (6 of 36) of surface samples from 3 patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient. Multivariable analysis indicated hypoxia at admission, polymerase chain reaction-positive nasopharyngeal swab (cycle threshold of ≤30) on or after surface sampling date, higher Charlson comorbidity score, and shorter time from onset of illness to sampling date were significantly associated with detection of SARS-CoV-2 RNA in surface samples.
Conclusions
The infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited.
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SciScore for 10.1101/2021.05.17.21257122: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Research ethics approval was granted by all participating The Toronto Invasive Bacterial Diseases Network hospitals (Sunnybrook’s Research Ethics Board, The Mount Sinai Hospital Research Ethics Board, Toronto East Health Network Research Ethics Board, Osler’s Research Ethics Board, and Scarborough Health Network’s Research Ethics Board).
Consent: Informed consent from all patients were obtained.Sex as a biological variable not detected. Randomization Mixed-effects logistic regression models with a random intercept for unique patient identification to account for clustering were constructed using backwards elimination. Blinding Cell cultures not showing any CPE were blind passaged onto fresh … SciScore for 10.1101/2021.05.17.21257122: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Research ethics approval was granted by all participating The Toronto Invasive Bacterial Diseases Network hospitals (Sunnybrook’s Research Ethics Board, The Mount Sinai Hospital Research Ethics Board, Toronto East Health Network Research Ethics Board, Osler’s Research Ethics Board, and Scarborough Health Network’s Research Ethics Board).
Consent: Informed consent from all patients were obtained.Sex as a biological variable not detected. Randomization Mixed-effects logistic regression models with a random intercept for unique patient identification to account for clustering were constructed using backwards elimination. Blinding Cell cultures not showing any CPE were blind passaged onto fresh Vero cells and observed for a further 5 days. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Vero E6 cells were seeded at a concentration of 3×105 cells/well in a six well-plate. Vero E6suggested: NoneCell cultures not showing any CPE were blind passaged onto fresh Vero cells and observed for a further 5 days. Verosuggested: CLS Cat# 605372/p622_VERO, RRID:CVCL_0059)Software and Algorithms Sentences Resources RNA extractions were performed using QIAmp viral RNA mini kit (Qiagen, https://www.qiagen.com) according to manufacturer’s instructions; samples were eluted into 40 uL. https://www.qiagen.comsuggested: (QIAGEN, RRID:SCR_008539)Statistical analysis: All analyses were conducted using Stata/SE 15·1 (StataCorp, College Station, Texas, USA; http://www.stata.com). StataCorpsuggested: (Stata, RRID:SCR_012763)http://www.stata.comsuggested: (COLELMS: Stata module to calculate Coles LMS values for growth data, RRID:SCR_007244)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:Our study has several limitations. First, although we had a large number of surface and air samples, the samples were recovered from only 78 patients, resulting in a relatively small effective sample size when accounting for clustering. While this still facilitated an exploratory analysis, this limited the power of our multivariable analysis as indicated by the wide confidence intervals for some of the significant variables in our final model. The small effective sample size also prohibited us from investigating factors associated with viable virus in environmental surface samples, including time from symptom onset. Second, the present work focused only on acute care inpatients, excluded critically ill individuals, and had first samples obtained several days after onset of illness. Working in acute care allowed us ready access to patient areas for sampling and clinical data to garner a granular understanding of environmental contamination in hospital settings, the generalizability of our findings to other settings is limited, particularly where room ventilation is highly variable such as homes, schools, long-term care residences, other workplaces, and public spaces. Additionally, it is important to note that these data were collected prior to the emergence of the SARS-CoV-2 variants of concern (VOCs) in late 2020. As such, it is unclear how our results apply to the transmission dynamics of VOCs. Finally, we did not use a standard curve for our RT-PCR analysis and could not ca...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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