Decontamination Methods of N95 Respirators Contaminated with SARS-CoV-2

In the preparation and response to the COVID-19 pandemic, a sufficient supply of personal protective equipment (PPE), particularly the face mask, is essential. Shortage of PPE due to growing demand leaves health workers at significant risk as they fight this pandemic on the frontline. As a mitigation measure to overcome potential mask shortages, these masks could be decontaminated and prepared for reuse. This review explored past scientific research on various methods of decontamination of the N95-type respirators and their efficiency against the SARS-CoV-2 virus. Ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide vapor (HPV) show great potential as an effective decontamination system. In addition, UVGI and HPV exhibit excellent effectiveness against the SARS-CoV-2 virus on the N95 respirator surfaces.

Mask decontamination methods (model N95) for respiratory protection: a rapid review

Background N95 respiratory protection masks are used by healthcare professionals to prevent contamination from 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 database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity for reliable fast evidences on this matter. Results A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation, 4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, 7 studies used autoclave, 3 studies used an electric rice cooker, 1 study used cleaning wipes, 1 study used bar soap, 1 study used water, 1 study used multi-purpose high-level disinfection cabinet, and another 1 study used chlorine dioxide. Five methods that are promising are as follows: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens. Conclusions We have presented the best available evidence on mask decontamination; nevertheless, its applicability is limited due to few studies on the topic and the lack of studies on real environments.

Using Low-Heat Decontamination to Allow N95 and PPE Reuse During the COVID-19 Pandemic

Background: US healthcare facilities experienced significant personal protective equipment (PPE) shortages, including N95 masks, in the spring and summer of 2020. The Centers for Disease Control and Prevention issued guidance for extended use, reprocessing, and reuse of N95s. Eskenazi Health (EH) implemented a program to reprocess N95s and other PPE on-site using low-heat decontamination (LHD). EH considered large-scale and small-scale ultraviolet (UV), hydrogen peroxide vapor, and LHD for on-site reprocessing of N95s. All of these methods allowed up to 3 reprocessing cycles according to most literature available at the time. However, each method differed in feasibility and acceptability to staff. EH chose to implement LHD based on both considerations. Methods: Numerous small-group meetings were held in April 2020 to determine the feasibility and acceptability of N95 reprocessing methods. Staff wanted a method that was easy for the end user, had quick turnaround, and allowed them to retrieve their own N95s. They favored a method that could be used for all PPE. EH had deployed numerous small UV machines that individuals could use for N95s. The UV machines could not be scaled up easily. To scale up, a multidisciplinary team comprising infection prevention, biomedical engineering, and sterile processing representatives reviewed available methods and implemented LHD. Biomedical engineers determined that existing blanket warmers could be reprogrammed and repurposed for low-heat decontamination. Food warmers were also available but were not needed. Biomedical engineers reprogrammed the blanket warmers to 70°C and developed a wicking system using a towel and water tray to maintain humidity; decontamination took 30 minutes. Testing runs determined that both N95s and eye protection tolerated LHD without apparent damage. Infection prevention staff developed a workflow in which staff deposited all PPE in a paper bag; the PPE bag was centrally reprocessed, marked (Figure 1), and returned to designated locations (Figure 2) for staff to retrieve their original PPE. Sterile processing staff facilitated the reprocessing workflow, and elective surgeries were canceled during the COVID-19 surge. Results: From April 20, 2020, to July 19, 2020, 7,512 units were decontaminated with LHD. If each N95 was sterilized thrice (4 uses per N95), then LHD reduced the need to purchase 22,536 N95s. Restarting elective surgeries decreased staff and support from sterile processing; the space was needed for other purposes; and N95 availability increased. All of these factors led to the discontinuation of LHD. Conclusions: LHD enables reprocessing of N95s and other PPE using existing assets. LHD is advantageous because of scalability and the capacity to provide staff with their own reprocessed PPE.Funding: NoDisclosures: None

Treatment with Dry Hydrogen Peroxide Accelerates the Decay of Severe Acute Syndrome Coronavirus-2 on Non-porous Hard Surfaces

Background. Disinfection of contaminated or potentially contaminated surfaces has become an integral part of the mitigation strategies for controlling coronavirus disease 2019. Whilst a broad range of disinfectants are effective in inactivating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), application of disinfectants has a low throughput in areas that receive treatments. Disinfection of large surface areas often involves the use of reactive microbiocidal materials, including ultraviolet germicidal irradiation, chlorine dioxide, and hydrogen peroxide vapor. Albeit these methods are highly effective in inactivating SARS-CoV-2, the deployment of these approaches creates unacceptable health hazards and precludes the treatment of occupied indoor spaces using existing disinfection technologies. Deployment of dry hydrogen peroxide (DHP) is an emerging pathogen reduction technology, which produces hydrogen peroxide in the ambient atmosphere at 5 and 25 parts per billion using a commercially available catalytic unit. The low concentration of hydrogen peroxide released using DHP technology has been found to be tolerated by humans in indoor spaces and is effective in inactivating bacterial pathogens responsible for nosocomial infections. In this study, the feasibility of using DHP in inactivating SARS-CoV-2 on contaminated surfaces in large indoor spaces was evaluated. Methods. Glass slides were inoculated with SARS-CoV-2 and treated with DHP for up to 24 hours. Residual infectious virus samples were eluted and titrated in African green monkey VeroE6 cells. Results. In comparison with the observed relatively high stability of SARS-CoV-2 on contaminated glass slides in the control group, residual infectious titers of glass slides inoculated with SARS-CoV-2 were significantly reduced after receiving 120 minutes of DHP treatment. Conclusions. The accelerated decay of SARS-CoV-2 on contaminated glass slides suggests that treatment with DHP can be an effective surface disinfection method for occupied indoor spaces.

Mask decontamination methods (model N95) for respiratory protection: a rapid review

Background: N95 respiratory protection masks are used by healthcare professionals to prevent contamination from 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 database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity on reliable fast evidences on this matter.Results: A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used Hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation,4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, seven studies used autoclave, three studies used electric rice cooker, one study used cleaning wipes, one study used bar soap, one study used water, one study used multi-purpose high-level disinfection cabinet and another one used chlorine dioxide. Five methods promising: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.Conclusions: We have presented the best available evidence on masks decontamination, nevertheless, its applicability are limited due to few studies on the topic and lack of studies on real environments.