Analysis of SteraMist ionized hydrogen peroxide technology in the sterilization of N95 respirators and other PPE

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Abstract

The COVID-19 pandemic has led to widespread shortages of personal protective equipment (PPE) for healthcare workers, including of N95 masks (filtering facepiece respirators; FFRs). These masks are intended for single use but their sterilization and subsequent reuse has the potential to substantially mitigate shortages. Here we investigate PPE sterilization using ionized hydrogen peroxide (iHP), generated by SteraMist equipment (TOMI; Frederick, MD), in a sealed environment chamber. The efficacy of sterilization by iHP was assessed using bacterial spores in biological indicator assemblies. After one or more iHP treatments, five models of N95 masks from three manufacturers were assessed for retention of function based on their ability to form an airtight seal (measured using a quantitative fit test) and filter aerosolized particles. Filtration testing was performed at a university lab and at a National Institute for Occupational Safety and Health (NIOSH) pre-certification laboratory. The data demonstrate that N95 masks sterilized using SteraMist iHP technology retain filtration efficiency up to ten cycles, the maximum number tested to date. A typical iHP environment chamber with a volume of ~ 80 m 3 can treat ~ 7000 masks and other items (e.g. other PPE, iPADs), making this an effective approach for a busy medical center.

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  1. SciScore for 10.1101/2020.04.19.20069997: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Evaluating sterility using biological indicators: The efficacy of sterilization was evaluated using Apex Biological Indicators (
    Apex Biological
    suggested: (California National Primate Research Center Analytical and Resource Core, RRID:SCR_000696)

    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:
    Thus, we do not believe our use of BIs rather than direct measurement of viral viability represents a significant limitation in the interpretation of the data. Two independent lines of evidence, one generated at a university laboratory and one at a commercial laboratory accredited to perform N95 mask certification to NIOSH/ISO/IEC standards, show that N95 masks decontaminated with iHP using SteraMist technology retain their performance with respect to filtration and inhalation resistance for at least five cycles, the maximum number tested. No deterioration was detected in masks tested 10 days post treatment. Quantitative fit testing of sterilized N95 masks confirms that they still form an airtight seal as required (in this case, tests were performed out to 10 cycles). Thus, sterilized N95 masks remain fully functional. Limitations of this study: Given the urgency of N95 mask shortages, we are reporting results obtained to date. However, some additional tests are currently underway to increase confidence in our specific findings and the practice of sterilizing and reusing N95 masks more generally. For example, while we report complete data on testing for up to 5 cycles on N95 masks, further evaluation of masks that have undergone 10 cycles of sterilization are underway at ICS Labs, using both instantaneous and fully loaded filtration testing. The tests described in this study were conducted using unused N95 masks. We do not yet have data on N95 masks used in an actual health c...

    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.

    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 checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.