Triaging of respiratory protective equipment on the assumed risk of SARS-CoV-2 aerosol exposure in patient-facing healthcare workers delivering secondary care: a rapid review
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Abstract
In patient-facing healthcare workers delivering secondary care, what is the evidence behind UK Government personal protective equipment (PPE) guidance on surgical masks versus respirators for SARS-CoV-2 protection?
Design
Two independent reviewers performed a rapid review. Appraisal was performed using Critical Appraisal Skills Programme checklists and Grading of Recommendations, Assessment, Development and Evaluations methodology. Results were synthesised by comparison of findings and appraisals.
Data sources
MEDLINE, Google Scholar, UK Government COVID-19 website and grey literature.
Eligibility criteria
Studies published on any date containing primary data comparing surgical facemasks and respirators specific to SARS-CoV-2, and studies underpinning UK Government PPE guidance, were included.
Results
Of 30 identified, only 3 laboratory studies of 14 different respirators and 12 surgical facemasks were found. In all three, respirators were significantly more effective than facemasks when comparing protection factors, reduction factors, filter penetrations, total inspiratory leakages at differing particle sizes, mean inspiratory flows and breathing rates. Tests included live viruses and inert particles on dummies and humans. In the six clinical studies (6502 participants) included the only statistically significant result found continuous use of respirators more effective in clinical respiratory illness compared with targeted use or surgical facemasks. There was no consistent definition of ‘exposure’ to determine the efficacy of respiratory protective equipment (RPE). It is difficult to define ‘safe’.
Conclusions
There is a paucity of evidence on the comparison of facemasks and respirators specific to SARS-CoV-2, and poor-quality evidence in other contexts. The use of surrogates results in extrapolation of non-SARS-CoV-2 specific data to guide UK Government PPE guidance. The appropriateness of this is unknown given the uncertainty over the transmission of SARS-CoV-2.
This means that the evidence base for UK Government PPE guidelines is not based on SARS-CoV-2 and requires generalisation from low-quality evidence of other pathogens/particles. There is a paucity of high-quality evidence regarding the efficacy of RPE specific to SARS-CoV-2. UK Government PPE guidelines are underpinned by the assumption of droplet transmission of SARS-CoV-2.
These factors suggest that the triaging of filtering face piece class 3 respirators might increase the risk of COVID-19 faced by some.
Article activity feed
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SciScore for 10.1101/2020.05.13.20101139: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization 18 All studies were included for qualitative analysis since it is noted that during a time of global crisis, the need for rapid evidence based on a novel virus may reduce the viability of gold-standard randomised controlled trials and shorten timelines for follow-up. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
No key resources detected.
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 …SciScore for 10.1101/2020.05.13.20101139: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement not detected. Randomization 18 All studies were included for qualitative analysis since it is noted that during a time of global crisis, the need for rapid evidence based on a novel virus may reduce the viability of gold-standard randomised controlled trials and shorten timelines for follow-up. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
No key resources detected.
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:• Strengths and weaknesses of the study: A CASP checklist critical appraisal was performed on this review. It was noted that there is a real paucity of evidence regarding RPE specific to SARS-CoV-2. HMG’s PPE guidance 4 was found to reference non-SARS-CoV-2 and non-FFP3 specific studies, therefore these were included for review. Any study design containing primary data was included. Non-English language studies were not included, though translated studies were screened. Due to the heterogeneity of study designs, and statistically insignificant results, it was not possible to perform a quantitative analysis. The potential harms of respirator use, such as pressure sores, is poorly documented and requires further study for mitigation and improvement. • Strengths and weaknesses in relation to other studies, discussing important differences in results: This review found that just one study directly compares FRSMs and respirators. Ng, et al.27 conclude that FRSMs and N95s are equally effective. Limitations of this study include retrospective design, small sample size and a wide range of scenarios defined as ‘exposure’. There is no stratification of confounding variables such as age, sex, health, community exposure to SARS-CoV-2, or exposure to other COVID-19 patients. In the participants tested, none tested positive for SARS-CoV-2 in either intervention. It is unclear how quantitative analysis was performed. No retrospective significant difference was found in SARS-CoV-2 test resul...
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.
- Thank you for including a protocol registration statement.
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