Surgical masks decontamination for reuse by members of the public: feasibility study and development of home-based methods

Abstract This study aims to propose decontamination methods that are suitable for use by members of the public to cope with the shortage of surgical masks during the current COVID-19 pandemic. 3-ply surgical masks were subjected to different decontamination protocols (heat, chemical, ultraviolet irradiation) to assess their abilities to achieve at least 4-log reduction of two common respiratory pathogens, H1N1 Influenza A virus, a single-stranded RNA enveloped virus similar to SARS-CoV-2 and Staphylococcus aureus, a Gram-positive bacterium that is more resistant to decontamination than single stranded RNA enveloped virus. Decontaminated surgical masks were assessed for differences in breathability, particle filtration efficiency and bacteria filtration efficiency as compared with non-decontaminated masks. The number of decontamination cycles that the 3-ply surgical masks could undergo without significant changes in breathability and filtration efficiencies were also determined. It was found that surgical masks decontaminated by either soaking for 60 min in 0.5% (v/v) aqueous hydrogen peroxide solution, or 30 min of soaking in 0.05% - 0.5% (v/v) aqueous sodium hypochlorite diluted from household bleach or ultraviolet irradiation by a surface dose of 13.5 kJ/m2 were able to achieve at least a 4-log reduction of both Staphylococcus aureus and H1N1 Influenza A virus spiked on surgical mask test swatches. No significant changes in breathability and filtration efficiencies of the surgical masks were observed after ten decontamination cycles of hydrogen peroxide or diluted bleach treatment or 30 cycles of ultraviolet irradiation.

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Vapor H2O2 sterilization as a decontamination method for the reuse of N95 respirators in the COVID-19 emergency

10.1101/2020.04.11.20062026 ◽

2020 ◽

Cited By ~ 5

Author(s):

Ebru Oral ◽

Keith K. Wannomae ◽

Rachel Connolly ◽

Joseph Gardecki ◽

Hui Min Leung ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Staphylococcus Aureus ◽

Medical Devices ◽

Healthcare Workers ◽

Hospital Environment ◽

Bacterial Spores ◽

Filter Efficiency ◽

Plasma Generation ◽

Log Reduction ◽

N95 Respirators

There are a variety of methods routinely used in the sterilization of medical devices using hydrogen peroxide (H2O2) including vaporization, plasma generation and ionization. Many of these systems are used for sterilization and are validated for bioburden reduction using bacterial spores.Here, we explored the benefits of using vaporized H2O2 (VHP) treatment of N95 respirators for emergency decontamination and reuse to alleviate PPE shortages for healthcare workers in the COVID-19 emergency. The factors that are considered for the effective reuse of these respirators are the fit, the filter efficiency and the decontamination/disinfection level for SARS-CoV-2, which is the causative virus for COVID-19 and other organisms of concern in the hospital environment such as methicillin-resistant Staphylococcus aureus or Clostridium difficile. WE showed that the method did not affect fit or filter efficiency at least for one cycle and resulted in a >6 log reduction in bacterial spores and >3.8 log reduction in the infectious SARS-CoV2 load on N95 respirators.

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A highly efficient cloth facemask

10.21203/rs.3.rs-322107/v3 ◽

2021 ◽

Author(s):

Christopher Cappa ◽

The San Francisco Opera Costume Department ◽

William Ristenpart ◽

Santiago Barreda ◽

Nicole Bouvier ◽

...

Keyword(s):

High Efficiency ◽

Separation Distance ◽

Filtration Efficiency ◽

Ambient Aerosols ◽

The Public ◽

Professional Singers ◽

Surgical Masks ◽

Mask Design ◽

N95 Respirators ◽

Better Than

Abstract Wearing masks and face coverings helps reduce transmission of respiratory diseases. Much prior research on mask filtration efficiency has focused on fabric type, with less consideration given to mask design and shape. Here, we present evidence that increasing the mouth-mask separation distance engenders an increase in the mask-fabric filtration efficiency towards expiratory aerosols emitted via vocalization, which we attribute to a decrease in the expiratory jet velocity and expansion of the breath-mask contact area. We further assess the performance of a new reusable cloth facemask design, originally made for, but not exclusive to, professional singers and having a large mouth-mask separation distance. With proper fitting, these masks achieve overall filtering efficiencies of >93% for both exhaled expiratory aerosols >0.5 microns in diameter from singing and speaking and for inhaled ambient aerosols, better than surgical masks and approaching N95 respirators. Air exchange between the mask deadspace and the ambient environment limits the extent of CO2 buildup and in inhaled air and maintains O2 levels near ambient. The mask design also provides for less inhibited mouth and jaw movement and lower relative humidity, suggesting it may provide a more palatable, high-efficiency alternative to medical-grade masks for the public.

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Decontamination and reuse of surgical masks and N95 filtering facepiece respirators during the COVID-19 pandemic: A systematic review

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.379 ◽

2020 ◽

Vol 42 (1) ◽

pp. 25-30 ◽

Cited By ~ 1

Author(s):

Kachorn Seresirikachorn ◽

Vorakamol Phoophiboon ◽

Thitiporn Chobarporn ◽

Kasenee Tiankanon ◽

Songklot Aeumjaturapat ◽

...

Keyword(s):

Systematic Review ◽

Hydrogen Peroxide ◽

Medical Personnel ◽

Physical Structure ◽

Filtration Efficiency ◽

Level Of Evidence ◽

Low Level ◽

Moist Heat ◽

Surgical Masks ◽

Hydrogen Peroxide Vapor

AbstractObjectives:Surgical masks and N95 filtering facepiece respirators (FFRs) prevent the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and protect medical personnel. Increased demands for surgical masks and N95 FFRs during the coronavirus disease 2019 (COVID-19) pandemic has resulted in the shortage crisis. However, there is no standard protocol for safe reuse of the N95 FFRs. In this systematic review, we aimed to evaluate the effectiveness of existing decontamination methods of surgical masks and N95 FFRs and provide evidence-based recommendations for selecting an appropriate decontamination method.Methods:We performed systematic searches of Ovid MEDLINE and Ovid EMBASE electronic databases. The last search was performed April 11, 2020. Any trials studying surgical masks and/or N95 FFRs decontamination were included. Outcomes were disinfections of virus and bacteria, restoration of the filtration efficiency, and maintenance of the physical structure of the mask.Results:Overall, 15 studies and 14 decontamination methods were identified. A low level of evidence supported 4 decontamination methods: ultraviolet (UV) germicidal irradiation (9 studies), moist heat (5 studies), microwave-generated steam (4 studies), and hydrogen peroxide vapor (4 studies). Therefore, we recommended these 4 methods, and we recommended against use were given for the other 10 methods.Conclusions:A low level of evidence supported the use of UV germicidal irradiation, moist heat, microwave-generated steam, and hydrogen peroxide vapor for decontamination and reuse of N95 FFRs. These decontamination methods were effective for viral and bacterial disinfection as well as restoration of the filtration efficiency, and the physical structure of the FFRs.

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Bronchoscopic findings in a child with pandemic novel H1N1 influenza a and methicillin-resistant Staphylococcus aureus

Pediatric Pulmonology ◽

10.1002/ppul.21306 ◽

2010 ◽

Vol 46 (1) ◽

pp. 92-95 ◽

Cited By ~ 3

Author(s):

Jack K. Sharp ◽

James Hereth ◽

Joseph Fasanello

Keyword(s):

Staphylococcus Aureus ◽

Influenza A ◽

Methicillin Resistant Staphylococcus Aureus ◽

H1n1 Influenza ◽

Methicillin Resistant ◽

Novel H1n1 Influenza

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From “don, doff, and discard” to “don, doff, and decontaminate” – determination of filtering facepiece respirator and surgical mask integrity and inactivation of a SARS-CoV-2 surrogate and a small non-enveloped virus following multiple-cycles of vaporised hydrogen peroxide, ultraviolet germicidal irradiation, and dry heat decontamination

10.1101/2021.01.15.21249866 ◽

2021 ◽

Author(s):

Louisa F. Ludwig-Begall ◽

Constance Wielick ◽

Olivier Jolois ◽

Lorène Dams ◽

Ravo M. Razafimahefa ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Filtration Efficiency ◽

Murine Norovirus ◽

Enveloped Virus ◽

Ultraviolet Germicidal Irradiation ◽

Dry Heat ◽

Multiple Cycle ◽

Multiple Cycles ◽

Respiratory Coronavirus ◽

Porcine Respiratory

ABSTRACTBackgroundAs the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens.AimWe provide information on the effect of time-dependent passive decontamination at room temperature and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination.MethodsMasks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations.Results and DiscussionInfectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused.

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An improved and highly efficient geometry for facemasks

10.21203/rs.3.rs-322107/v2 ◽

2021 ◽

Author(s):

Christopher Cappa ◽

William Ristenpart ◽

Santiago Barreda ◽

Nicole Bouvier ◽

Anthony Wexler ◽

...

Keyword(s):

High Efficiency ◽

Separation Distance ◽

Filtration Efficiency ◽

Ambient Aerosols ◽

The Public ◽

Professional Singers ◽

Surgical Masks ◽

Mask Design ◽

N95 Respirators ◽

Better Than

Abstract Wearing masks and face coverings helps reduce transmission of respiratory diseases. Much prior research on mask filtration efficiency has focused on fabric type, with little consideration given to mask geometry. Here, we present evidence that increasing the mouth-mask separation distance engenders an increase in the mask-fabric filtration efficiency towards expiratory aerosols emitted via vocalization, which we attribute to a decrease in the expiratory jet velocity. We further assess the performance of a new reusable cloth facemask design, originally made for professional singers and having a large mouth-mask separation distance. With proper fitting, these masks achieve overall filtering efficiencies of >93% for both exhaled expiratory aerosols from singing and speaking and for inhaled ambient aerosols, better than surgical masks and approaching N95 respirators. The mask design also provides for less inhibited mouth and jaw movement, suggesting it may provide a more palatable, high-efficiency alternative to medical-grade masks for the public.

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Validation of N95 filtering facepiece respirator decontamination methods available at a large university hospital

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa610 ◽

2020 ◽

Cited By ~ 1

Author(s):

Krista R Wigginton ◽

Peter J Arts ◽

Herek Clack ◽

William J Fitzsimmons ◽

Mirko Gamba ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Influenza A ◽

Hepatitis Virus ◽

Biological Indicator ◽

Filtration Efficiency ◽

University Hospital ◽

Murine Hepatitis Virus ◽

Gas Plasma ◽

Bacteria And Fungi ◽

N95 Respirators

Abstract Background Due to unprecedented shortages in N95 filtering facepiece respirators, healthcare systems have explored N95 reprocessing. No single, full-scale reprocessing publication has reported an evaluation including multiple viruses, bacteria, and fungi along with respirator filtration and fit. Methods We explored reprocessing methods using new 3M™ 1860 N95 respirators, including moist (50-75% relative humidity, RH) heat (80-82 oC for 30 minutes), ethylene oxide (EtO), pulsed xenon UV-C (UV-PX), hydrogen peroxide gas plasma (HPGP), and hydrogen peroxide vapor (HPV). Respirator samples were analyzed using four viruses (MS2, phi6, influenza A virus (IAV), murine hepatitis virus (MHV)), three bacteria (Escherichia coli, Staphylococcus aureus, Geobacillus stearothermophilus spores and vegetative bacteria), and Aspergillus niger. Different application media were tested. Decontaminated respirators were evaluated for filtration integrity and fit. Results Heat with moderate RH most effectively inactivated virus, resulting in reductions of >6.6 log10 MS2, >6.7 log10 Phi6, >2.7 log10 MHV, and >3.9 log10 IAV and prokaryotes, except for G. stearothermohphilus. HPV was moderately effective at inactivating tested viruses, resulting in 1.5 to >4 log10 observable inactivation. S. aureus inactivation by HPV was limited. Filtration efficiency and proper fit were maintained following 5 cycles of heat with moderate RH, and HPV. Although effective at decontamination, HPGP resulted in decreased filtration efficiency, and EtO treatment raised toxicity concerns. Observed virus inactivation varied depending upon the application media used. Conclusion Both moist heat and HPV are scalable N95 reprocessing options as they achieve high levels of biological indicator inactivation while maintaining respirator fit and integrity.

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