Investigating Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Surface and Air Contamination in an Acute Healthcare Setting During the Peak of the Coronavirus Disease 2019 (COVID-19) Pandemic in London
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Abstract
Background
We evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surface and air contamination during the coronavirus disease 2019 (COVID-19) pandemic in London.
Methods
Prospective, cross-sectional, observational study in a multisite London hospital. Air and surface samples were collected from 7 clinical areas occupied by patients with COVID-19 and a public area of the hospital. Three or four 1.0-m3 air samples were collected in each area using an active air sampler. Surface samples were collected by swabbing items in the immediate vicinity of each air sample. SARS-CoV-2 was detected using reverse-transcription quantitative polymerase chain reaction (PCR) and viral culture; the limit of detection for culturing SARS-CoV-2 from surfaces was determined.
Results
Viral RNA was detected on 114 of 218 (52.3%) surfaces and in 14 of 31 (38.7%) air samples, but no virus was cultured. Viral RNA was more likely to be found in areas immediately occupied by COVID-19 patients than in other areas (67 of 105 [63.8%] vs 29 of 64 [45.3%]; odds ratio, 0.5; 95% confidence interval, 0.2–0.9; P = .025, χ2 test). The high PCR cycle threshold value for all samples (>30) indicated that the virus would not be culturable.
Conclusions
Our findings of extensive viral RNA contamination of surfaces and air across a range of acute healthcare settings in the absence of cultured virus underlines the potential risk from environmental contamination in managing COVID-19 and the need for effective use of personal protective equipment, physical distancing, and hand/surface hygiene.
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SciScore for 10.1101/2020.05.24.20110346: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture: Vero E6 (African Green monkey kidney) and Caco2 (human colon carcinoma) cells were used to culture virus from air and environmental samples. Caco2suggested: CLS Cat# 300137/p1665_CaCo-2, RRID:CVCL_0025)A dilution series from solution containing 8.25×106 PFU/mL SARS-CoV-2 (titred by plaque assay in Vero cells) from 10-3 to 10-6 (covering Ct values from 26 to 36) was produced in DMEM and 50 μL inoculated in triplicate … SciScore for 10.1101/2020.05.24.20110346: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture: Vero E6 (African Green monkey kidney) and Caco2 (human colon carcinoma) cells were used to culture virus from air and environmental samples. Caco2suggested: CLS Cat# 300137/p1665_CaCo-2, RRID:CVCL_0025)A dilution series from solution containing 8.25×106 PFU/mL SARS-CoV-2 (titred by plaque assay in Vero cells) from 10-3 to 10-6 (covering Ct values from 26 to 36) was produced in DMEM and 50 μL inoculated in triplicate onto the surface of plastic (standard keyboard key) or stainless steel (2 × 1 × 0.2 cm) pieces. Verosuggested: None140 μL was used for RNA extraction and qPCR immediately (0 days post inoculation, dpi) and after incubation for 7 days in a 24-well plate with VeroE6 cells (7 dpi). VeroE6suggested: JCRB Cat# JCRB1819, RRID:CVCL_YQ49)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:However, a larger sample size is required to understand this risk Our study has important strengths and limitations. Strengths include our sampling strategy encompassing contemporaneous surface and air samples from a range of clinical services including both patient care and non-patient care areas, specifically, we included operating theatres and areas dedicated to known and potential AGPs; each sample was tested using PCR and also viral culture, and we performed laboratory viral culture experiments to quality our findings; the sampling was conducted during the peak of the pandemic (and so likely represents a worst-case scenario) in a European hospital group. Limitations include not collecting patient samples to better understand how our findings links to patient samples, particularly during tracheostomies and AGPs; no asymptomatic patient or staff testing ongoing at the time of sampling, which means patients and staff without known COVID-19 could have been shedding SARS-CoV-2 and this would explain the detection of SARS-CoV-2 RNA in non-patient care areas; challenges in interpreting the significance of samples with low viral loads,; a lack of resolution of particle sizes for contamination of the air; and no longitudinal sampling was performed so these findings represent a “snapshot”. Our findings may have implications for future policy and guidelines. Most international guidelines recommend enhanced surfaces disinfection during the management of COVID-19. For example, Public...
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.
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SciScore for 10.1101/2020.05.24.20110346: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture: Vero E6 ( African Green monkey kidney ) and Caco2 ( human colon carcinoma ) cells were used to culture virus from air and environmental samples . Caco2suggested: CLS Cat# 300137/p1665_CaCo-2, CVCL_0025A dilution series from solution containing 8.25x106 PFU/mL SARSCoV-2 ( titred by plaque assay in Vero cells ) from 10-3 to 10-6 ( covering Ct values … SciScore for 10.1101/2020.05.24.20110346: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture: Vero E6 ( African Green monkey kidney ) and Caco2 ( human colon carcinoma ) cells were used to culture virus from air and environmental samples . Caco2suggested: CLS Cat# 300137/p1665_CaCo-2, CVCL_0025A dilution series from solution containing 8.25x106 PFU/mL SARSCoV-2 ( titred by plaque assay in Vero cells ) from 10-3 to 10-6 ( covering Ct values from 26 to 36 ) was produced in DMEM and 50 µL inoculated in triplicate onto the surface of plastic ( standard keyboard key ) or stainless steel ( 2 x 1 x 0.2 cm ) pieces . Verosuggested: NoneSamples with an increase in copy numbers for the E gene ( reduced Ct values relative to the original samples ) after propagation in Vero E6 cells were considered positive by viral culture. Vero E6suggested: CVCL_XD71Results from OddPub: We did not find a statement about open data. We also did not find a statement about open code. Researchers are encouraged to share open data when possible (see Nature blog).
About SciScore
SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore is not a substitute for expert review. SciScore checks for the presence and correctness of RRIDs (research resource identifiers) in the manuscript, and detects sentences that appear to be missing RRIDs. SciScore also checks to make sure that rigor criteria are addressed by authors. It does this by detecting sentences that discuss criteria such as blinding or power analysis. SciScore does not guarantee that the rigor criteria that it detects are appropriate for the particular study. Instead it assists authors, editors, and reviewers by drawing attention to sections of the manuscript that contain or should contain various rigor criteria and key resources. For details on the results shown here, including references cited, please follow this link.
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