Can N95 Respirators Be Reused after Disinfection? How Many Times?

Liao, Lei; Wang, Xiao; Zhao, Mervin; Yu, Xuanze; Wang, Haotian; Wang, Qiqi; Chu, Steven; Cui, Yi

doi:10.1021/acsnano.0c03597

Cited by 402 publications

(621 citation statements)

References 32 publications

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“…The use of dry heat (temperatures between 70 and 85 °C) as a decontamination method did not affect the structural characteristics of the masks under various humidity conditions (≤ 100% RH). 25,27 The ltering e ciency remained acceptable up to 50 cycles. 27 At 70 ºC the method was effective against the SARS-CoV-2.…”

Section: Dry Heatmentioning

confidence: 94%

“…25,27 The ltering e ciency remained acceptable up to 50 cycles. 27 At 70 ºC the method was effective against the SARS-CoV-2. 25…”

Section: Dry Heatmentioning

confidence: 94%

“…Five studies 20,23,27,30,31 evaluated the effect of moist heat between 60 and 100 °C. The method did not alter mask t, odor or comfort.…”

Section: Moist Heat / Pasteurizationmentioning

confidence: 99%

“…The method did not alter mask t, odor or comfort. 20,23,27,30,31 In one study 27 ltering capacity was reduced to 80% after 10 cycles. Moist heat (65±5 °C for 3 h) was also effective in eliminating H1N1 30 and H5N1 20 viruses.…”

Section: Moist Heat / Pasteurizationmentioning

confidence: 99%

“…Different methods of decontamination with ethanol were tested: spray, 25 immersion, 27,35 and pipette drips. 34 Results were divergent between methods.…”

Section: Ethanolmentioning

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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Abstract 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 April 2020 using a simplification of the formal systematic review process. A total of 166 articles were retrieved of which 17 laboratory-based studies were selected. Results: Two of the studies only examined the effectiveness of decontamination methods, seven only reported on the maintenance of mask integrity, and eight considered both outcomes. Twelve decontamination methods were included in the studies. 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. Nonetheless, five methods appear promising: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.

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Section: Dry Heatmentioning

confidence: 94%

“…25,27 The ltering e ciency remained acceptable up to 50 cycles. 27 At 70 ºC the method was effective against the SARS-CoV-2. 25…”

Section: Dry Heatmentioning

confidence: 94%

“…Five studies 20,23,27,30,31 evaluated the effect of moist heat between 60 and 100 °C. The method did not alter mask t, odor or comfort.…”

Section: Moist Heat / Pasteurizationmentioning

confidence: 99%

Section: Moist Heat / Pasteurizationmentioning

confidence: 99%

“…Different methods of decontamination with ethanol were tested: spray, 25 immersion, 27,35 and pipette drips. 34 Results were divergent between methods.…”

Section: Ethanolmentioning

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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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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Copper@ZIF‐8 Core‐Shell Nanowires for Reusable Antimicrobial Face Masks

Kumar

Sharma

Chen

et al. 2020

Adv Funct Materials

122

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SARS‐CoV‐2 and other respiratory viruses spread via aerosols generated by infected people. Face masks can limit transmission. However, widespread use of disposable masks consumes tremendous resources and generates waste. Here, a novel material for treating blown polypropylene filtration media used in medical‐grade masks to impart antimicrobial activity is reported. To produce thin copper@ZIF‐8 core‐shell nanowires (Cu@ZIF‐8 NWs), Cu NWs are stabilized using a pluronic F‐127 block copolymer, followed by growth of ZIF‐8 to obtain uniform core‐shell structures. The Cu@ZIF‐8 NWs are applied to filtration media by dip coating. Aerosol filtration efficiency decreases upon exposure to ethanol (solvent for dip‐coating), but increases with addition of Cu@ZIF‐8 NWs. Cu@ZIF‐8 NWs shows enhanced antibacterial activity, compared to Cu NWs or ZIF‐8 alone, against Streptococcus mutans and Escherichia coli . Antiviral activity against SARS‐CoV‐2 is assayed using virus‐infected Vero E6 cells, demonstrating 55% inhibition of virus replication after 48 h by 1 µg of Cu@ZIF‐8 NWs per well. Cu@ZIF‐8 NWs’ cytotoxicity is tested against four cell lines, and their effect on inflammatory response in A549 cells is examined, demonstrating good biocompatibility. This low‐cost, scalable synthesis and straightforward deposition of Cu@ZIF‐8 NWs onto filter media has great potential to reduce disease transmission, resource consumption, and environmental impact of waste.

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Can N95 Respirators Be Reused after Disinfection? How Many Times?

Cited by 402 publications

References 32 publications

Decontamination Methods for Respiratory Protection Mask Model N95: A Rapid Review

Decontamination Methods for Respiratory Protection Mask Model N95: A Rapid Review

Filtering Facepiece Respirator (N95 Respirator) Reprocessing

Copper@ZIF‐8 Core‐Shell Nanowires for Reusable Antimicrobial Face Masks

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