Addressing decontaminated respirators: Some methods appear to damage mask integrity and protective function

Peltier, Richard E.; Wang, Jiayuan; Hollenbeck, Brian; Lanza, Jennifer; Furtado, Ryan M.; Cyr, Jay; Ellison, Richard T.; Kobayashi, Kimiyoshi

doi:10.1017/ice.2020.332

Cited by 18 publications

(33 citation statements)

References 8 publications

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“…Hydrogen peroxide Hydrogen peroxide was evaluated in its liquid, plasma and gas/vapor forms by nineteen laboratory studies. 28,[35][36][37][38][39]43,47,[53][54][55][56][57]60,61,64,68,70,71 The effect of hydrogen peroxide on the ltering capacity varied according to the method used. Hydrogen peroxide plasma led to changes in the masks' metallic nasal clips 61 and degradation in their ltering performance.…”

Section: Characterization Of the Included Studiesmentioning

confidence: 99%

“…The effect of ultraviolet germicidal irradiation on N95 respirators masks was evaluated by 21 studies 24,28,30,33,37,42,[45][46][47][48]50,51,53,56,[58][59][60][61][62][63]65 and there was a difference between studies in relation to UVGI doses and application of time periods. In general, UVGI did not affect the integrity and ability of the masks to lter aerosols or adapt to the face, nor did it leave a smell, irritating/toxic residues, or create important changes in appearance even when multiple cycles were performed.…”

Section: Ultraviolet Germicidal Irradiation (Uvgi)mentioning

confidence: 99%

“…In general, UVGI did not affect the integrity and ability of the masks to lter aerosols or adapt to the face, nor did it leave a smell, irritating/toxic residues, or create important changes in appearance even when multiple cycles were performed. 24,28,30,37,42,45,46,48,53,56,[60][61][62] However, different commercial brands of N95 models resisted differently in terms of performance penetration after multiple cycles and doses applied. 46 The method was effective against the in uenza virus H5N1, 24 SARS-CoV-2, 28 bacteriophages MS2, 30 and in uenza virus H1N1.…”

Section: Ultraviolet Germicidal Irradiation (Uvgi)mentioning

confidence: 99%

“…Ten studies 29,37,42,44,45,53,56,60,61,63 evaluated the use of hypochlorite at different concentrations and application methods (Table 3, Supplementary material 4). The maintenance of mask integrity and ltering capacity varied between studies.…”

Section: Sodium Hypochlorite (Naclo)mentioning

confidence: 99%

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Decontamination methods for respiratory protection mask model N95: a rapid review

Probst

Guerrero

Cardoso

et al. 2020

Preprint

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Background: N95 respiratory protection masks are used by healthcare professionals to prevent contamination with infectious microorganisms transmitted by droplets or aerosols.Methods: We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The review was carried out in September 2020 using a simplification of the formal systematic review process, which simplified the stages of a complete systematic review, including the exclusion of an assessment of study methodology.Results: A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. Hydrogen peroxide was evaluated by 19 laboratory studies, ultraviolet germicidal irradiation by 21, ethylene oxide by 4, dry heat by 11, moist heat by 9, ethanol by 5, isopropanol solution by 2, microwave oven by 11, sodium hypochlorite by 10, autoclave by 7, electric rice cooker by 3, cleaning wipes by 1, bar soap and water 1, multi-Purpose High-Level Disinfection Cabinet by 1 and chlorine dioxide by 1. Five methods appear promising: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.Conclusions: Positive results should be considered with caution as they represent a small number of studies, reflect ideal laboratory conditions, and may have limited applicability in realistic situations and for health systems.

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Section: Characterization Of the Included Studiesmentioning

confidence: 99%

Section: Ultraviolet Germicidal Irradiation (Uvgi)mentioning

confidence: 99%

Section: Ultraviolet Germicidal Irradiation (Uvgi)mentioning

confidence: 99%

Section: Sodium Hypochlorite (Naclo)mentioning

confidence: 99%

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Decontamination methods for respiratory protection mask model N95: a rapid review

Probst

Guerrero

Cardoso

et al. 2020

Preprint

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“…Similarly, UVGI has been shown to inactivate viruses such as H1N1 without compromising mask functionality [ 14 ]. However, the poor penetration of UV-C photons into the filter layers of the N95 masks requires high doses (>270 kJ/ m 2 ) to be applied that can result in 20–51% loss in strap strength [ 15 , 16 ]. Hydrogen peroxide vapor is the most widely used N95 mask decontamination method and has been demonstrated to support endospore reduction with negligible effects on mask functionality [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process

Hasani

Campbell

et al. 2021

PLoS ONE

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A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2–6% v/v) but was significantly (P<0.05) higher when H2O2 was introduced into the unit at 40 ml/min compared to 20 ml/min. A suitable treatment for N95 masks was identified as 3% v/v hydrogen peroxide delivered into the gAOP reactor at 40 ml/min with continuous introduction of ozone gas and a UV-C dose of 113 mJ/cm2 (30 s processing time). The treatment supported >6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (<1 ppm) in gAOP treated masks. The optimized gAOP treatment could also support >6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality.

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Filtering Facepiece Respirator (N95 Respirator) Reprocessing

Schumm

Hadaya

Mody

et al. 2021

JAMA

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IMPORTANCE The COVID-19 pandemic has resulted in a persistent shortage of personal protective equipment; therefore, a need exists for hospitals to reprocess filtering facepiece respirators (FFRs), such as N95 respirators. OBJECTIVE To perform a systematic review to evaluate the evidence on effectiveness and feasibility of different processes used for decontaminating N95 respirators. EVIDENCE REVIEW A search of PubMed and EMBASE (through January 31, 2021) was completed for 5 types of respirator-decontaminating processes including UV irradiation, vaporized hydrogen peroxide, moist-heat incubation, microwave-generated steam, and ethylene oxide. Data were abstracted on process method, pathogen removal, mask filtration efficiency, facial fit, user safety, and processing capability. FINDINGS Forty-two studies were included that examined 65 total types of masks. All were laboratory studies (no clinical trials), and 2 evaluated respirator performance and fit with actual clinical use of N95 respirators. Twenty-seven evaluated UV germicidal irradiation, 19 vaporized hydrogen peroxide, 9 moist-heat incubation, 10 microwave-generated steam, and 7 ethylene oxide. Forty-three types of N95 respirators were treated with UV irradiation. Doses of 1 to 2 J/cm 2 effectively sterilized most pathogens on N95 respirators (>10 3 reduction in influenza virus [4 studies], MS2 bacteriophage [3 studies], Bacillus spores [2 studies], Escherichia virus MS2 [1 study], vesicular stomatitis virus [1 study], and Middle East respiratory syndrome virus/SARS-CoV-1 [1 study]) without degrading respirator components. Doses higher than 1.5 to 2 J/cm 2 may be needed based on 2 studies demonstrating greater than 10 3 reduction in SARS-CoV-2. Vaporized hydrogen peroxide eradicated the pathogen in all 7 efficacy studies (>10 4 reduction in SARS-CoV-2 [3 studies] and >10 6 reduction of Bacillus and Geobacillus stearothermophilus spores [4 studies]). Pressurized chamber systems with higher concentrations of hydrogen peroxide caused FFR damage (6 studies), while open-room systems did not degrade respirator components. Moist heat effectively reduced SARS-CoV-2 (2 studies), influenza virus by greater than 10 4 (2 studies), vesicular stomatitis virus (1 study), and Escherichia coli (1 study) and preserved filtration efficiency and facial fit for 11 N95 respirators using preheated containers/chambers at 60°C to 85°C (5 studies); however, diminished filtration performance was seen for the Caron incubator. Microwave-generated steam (1100-W to 1800-W devices; 40 seconds to 3 minutes) effectively reduced pathogens by greater than 10 3 (influenza virus [2 studies], MS2 bacteriophage [3 studies], and Staphylococcus aureus [1 study]) and maintained filtration performance in 10 N95 respirators; however, damage was noted in least 1 respirator type in 4 studies. In 6 studies, ethylene oxide preserved respirator components in 16 N95 respirator types but left residual carcinogenic by-product (1 study). CONCLUSIONS AND RELEVANCE Ultraviolet germicidal irradiation, vaporized h...

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Addressing decontaminated respirators: Some methods appear to damage mask integrity and protective function

Cited by 18 publications

References 8 publications

Decontamination methods for respiratory protection mask model N95: a rapid review

Decontamination methods for respiratory protection mask model N95: a rapid review

Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process

Filtering Facepiece Respirator (N95 Respirator) Reprocessing

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