Skip to main content Accessibility help
×
Home
Hostname: page-component-5bf98f6d76-nn2qz Total loading time: 1.184 Render date: 2021-04-22T11:02:35.668Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": false, "newCiteModal": false, "newCitedByModal": true }

Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Published online by Cambridge University Press:  26 March 2020

Sean Wei Xiang Ong
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore
Yian Kim Tan
Affiliation:
DSO National Laboratories, Singapore, Singapore
Stephanie Sutjipto
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore
Po Ying Chia
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
Barnaby Edward Young
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore
Marcus Gum
Affiliation:
DSO National Laboratories, Singapore, Singapore
Sok Kiang Lau
Affiliation:
DSO National Laboratories, Singapore, Singapore
Monica Chan
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore
Shawn Vasoo
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
Shehara Mendis
Affiliation:
Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore
Boon Kiat Toh
Affiliation:
Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore
Janice Leong
Affiliation:
Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore
Timothy Barkham
Affiliation:
Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
Brenda Sze Peng Ang
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
Boon Huan Tan
Affiliation:
DSO National Laboratories, Singapore, Singapore
Yee-Sin Leo
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
Kalisvar Marimuthu
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
Michelle Su Yen Wong
Affiliation:
DSO National Laboratories, Singapore, Singapore
Oon Tek Ng
Affiliation:
National Centre for Infectious Diseases, Singapore, Singapore Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
Corresponding
Rights & Permissions[Opens in a new window]

Abstract

Type
Research Brief
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
© 2020 by The Society for Healthcare Epidemiology of America. All rights reserved

Local transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in Singapore has been reported. Reference Young, Ong and Kalimuddin1 As the pandemic spreads globally, increased utilization and shortages of personal protective equipment (PPE) are expected. Although extended PPE use would mitigate utilization rate, its safety is unknown. At the National Centre for Infectious Diseases, recommendations for healthcare workers (HCWs) in contact with known or suspected patients are in concordance with the US Centers for Disease Control and Prevention, which recommends gloves, gown, respiratory protection (eg, disposable N95 respirator), and eye protection (eg, goggles or disposable face shield), without the use of shoe covers. 2

An initial pilot study showed no contamination of N95 and disposable face visors after patient care, although in 1 instance, SARS-CoV-2 nucleic acid was detected on the front surface of an HCW’s shoe. Reference Ong, Tan and Chia3 To evaluate the safety of extended PPE use, we conducted a 1-day PPE sampling study on HCWs caring for confirmed COVID-19 patients to ascertain the per contact episode risk of PPE contamination with SARS-CoV-2.

Methods

The PPE samples were collected by 5 trained personnel using a standardized technique with Puritan EnviroMax Plus premoistened sterile swabs (Puritan Medical Products, Guilford, ME) from the entire front of goggles, the front surface of N95 respirator, and the front surfaces of shoes of 30 HCWs (Table 1) exiting patient rooms. Gloves and gowns were not swabbed because these are disposed after each use. Data on HCW category and details of activity in the room were recorded. Patients with positive SARS-CoV-2 PCR assays within the prior 48 hours were selected, and clinical data (ie, day of illness, presence of symptoms, and cycle threshold [Ct] value of clinical PCR) were obtained from the medical record. Environmental samples were tested using specific real-time RT-PCR methods targeting the SARS-CoV-2 RNA-dependent RNA polymerase (RdRP) and E genes. Reference Corman, Landt and Kaiser4

Table 1. Characteristics of PPE Samples Collected and Relevant Patient Clinical Data

Note. Ct, cycle threshold. Cycle threshold refers to the number of cycles required for the fluorescent signal to cross the threshold in RT-PCR; a lower cycle threshold value indicates a higher viral load.

Results

In total, 15 patients (7 women and 8 men) were selected. Patient characteristics varied by day of illness (median, day 14; interquartile range [IQR], 8.25–17.25), presence of symptoms (63% symptomatic), and clinical PCR Ct value (median, 30.08; IQR 28.85–30.86). No patient required ventilatory support and no aerosol-generating procedures were carried out prior to or during sampling. All 90 samples from 30 HCWs (doctors, nurses, and cleaners) were negative (Table 1). The median time spent in the patient’s room overall was 6 minutes (IQR, 5–10): 8 minutes for doctors, 7 minutes for nurses, and 3 minutes for cleaning staff. Activities ranged from casual contact (eg, administering medications or cleaning) to closer contact (eg, physical examination or collection of respiratory samples).

Discussion

Our study had several limitations. One limitation of our study was the use of surface swabs for sampling the surface of N95 masks rather than processing masks in extraction buffers with detergents, which is a method that has been used for isolation of influenza from N95 respirators. Reference Blachere, Lindsley and McMillen5 Surface swabbing may be insufficient for the detection of entrapped viral particles. Second, all patients were in airborne infection isolation rooms with 12 air exchanges per hour, and these results may not be generalizable to other room configurations. Third, we did not assess the concomitant level of viral contamination of the environment in this study to correlate with the level of PPE contamination.

Previous laboratory studies have demonstrated that viruses, such as SARS-CoV and human coronavirus 229E, can remain viable on PPE items, including latex gloves and disposable gowns, Reference Lai, Cheng and Lim6Reference Casanova, Rutala, Weber and Sobsey8 but these studies were not performed in clinical settings. Despite the potential for extensive environmental contamination by SARS-CoV-2, we did not find similar contamination of PPE after patient contact. These results provide assurance that extended use of N95 and goggles with strict adherence to environmental and hand hygiene while managing SARS-CoV-2 patients could be a safe option.

Acknowledgments

We thank Ding Ying and other members of the Infectious Diseases Research and Training Office for assistance with sample processing as well as all members of the National Centre for Infectious Diseases COVID-19 Outbreak Research Team: Poh Lian Lim, David Chien Lye, Cheng Chuan Lee, Li Min Ling, Lawrence Lee, Tau Hong Lee, Chen Seong Wong, Sapna Sadarangani, Ray Lin, Deborah HL Ng, Mucheli Sadasiv, Chiaw Yee Choy, Glorijoy Tan, Frederico Dimatatac, Isais Florante Santos, Go Chi Jong, Yu Kit Chan, Jun Yang Tay, and Pei Hua Lee. We also thank the DSO environmental detection team and Clinical diagnostics team for BSL3 sample processing and analysis; and logistics and repository team for transport of biohazard material, inventory, and safekeeping of received items.

Financial support

Funding for this study was provided by DSO National Laboratories. Ng Ot is supported by an NMRC Clinician Scientist Award (grant no. MOH-000276). Dr Kalisvar Marimuthu is supported by NMRC CS-IRG (grant no. CIRG18Nov-0034).

Conflicts of interest

All authors report no conflicts of interest relevant to this article.

Footnotes

a

Authors of equal contribution.

b

Authors of equal contribution.

References

Young, BE, Ong, SWX, Kalimuddin, S, et al. Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore. JAMA. Published online March 3, 2020. doi: 10.1001/jama.2020.3204.CrossRefGoogle Scholar
Interim infection prevention and control recommendations for patients with known or patients under investigation for 2019 novel coronavirus (2019-nCoV) in a healthcare setting. Centers for Disease Control and Prevention website. https://www.cdc.gov/coronavirus/2019-nCoV/hcp/infection-control.html. Published 2020. Accessed March 30, 2020.Google Scholar
Ong, SWX, Tan, YK, Chia, PY, et al. Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient. JAMA. Published online March 4, 2020. doi: 10.1001/jama.2020.3227.CrossRefGoogle Scholar
Corman, VM, Landt, O, Kaiser, M, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill 2020;25:2000045.CrossRefGoogle ScholarPubMed
Blachere, FM, Lindsley, WG, McMillen, CM, et al. Assessment of influenza virus exposure and recovery from contaminated surgical masks and N95 respirators. J Virol Methods 2018;260:98106.CrossRefGoogle ScholarPubMed
Lai, MY, Cheng, PK, Lim, WW. Survival of severe acute respiratory syndrome coronavirus. Clin Infect Dis 2005;41:e67e71.CrossRefGoogle ScholarPubMed
Sizun, J, Yu, MW, Talbot, PJ. Survival of human coronaviruses 229E and OC43 in suspension and after drying onsurfaces: a possible source ofhospital-acquired infections. J Hosp Infect 2000;46:5560.CrossRefGoogle ScholarPubMed
Casanova, L, Rutala, WA, Weber, DJ, Sobsey, MD. Coronavirus survival on healthcare personal protective equipment. Infect Control Hosp Epidemiol 2010;31:560561.CrossRefGoogle ScholarPubMed

Altmetric attention score

Full text views

Full text views reflects PDF downloads, PDFs sent to Google Drive, Dropbox and Kindle and HTML full text views.

Total number of HTML views: 2254
Total number of PDF views: 10316 *
View data table for this chart

* Views captured on Cambridge Core between 26th March 2020 - 22nd April 2021. This data will be updated every 24 hours.

You have Access
Open access

Send article to Kindle

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Available formats
×

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Available formats
×

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Available formats
×
×

Reply to: Submit a response


Your details


Conflicting interests

Do you have any conflicting interests? *