COVID-19: Disinfection of N95 Single-Use Filtering Facepiece Respirators
This publication uses the term “disinfection” of N95 masks to refer to the chemical or physical process that inactivates infectious agents. It should be noted that the various reference publications and documents on the subject consulted by the Centre d’expertise en retraitement des dispositifs médicaux (CERDM) use the terms “decontamination,” “disinfection,” or both. The CERDM has chosen the term “disinfection” to conform to the reprocessing nomenclature that is generally accepted in Canada (CSA Z314.18). According to this nomenclature, the term decontamination is more general and includes the process of cleaning followed by the inactivation of infectious agents. However, in the context of reprocessing of N95 masks, only one step, aimed at inhibiting various pathogenic microorganisms, is performed; therefore it seems more accurate to use the term “disinfection”.
The CERDM evaluated the available options for disinfection of single-use N95 filtering facepiece respirators (masks) in the context of a shortage of filtering facepiece respirators (FFRs) in health care facilities due to the COVID-19 pandemic (INSPQ, 2020a). This represents a solution of last resort to be applied only when there is a real shortage and when all other strategies for addressing the shortage of N95 masks are insufficient, as it is not consistent with the guidelines of regulatory authorities regarding the reprocessing of single-use medical devices (SUMDs). This effort is being undertaken with the aim of identifying alternative strategies that can be added to the measures already available, to provide the best possible protection for workers in the event of a shortage.
This document is intended for decision makers, managers and clinical personnel involved in medical device reprocessing (MDR). It presents the technologies approved by Health Canada in the COVID-19 context as well as a promising - although as yet unauthorized - option for disinfecting N95 masks.
The CERDM carried out a non-exhaustive review of the literature on the options for disinfecting N95 masks and contacted manufacturers of available equipment to identify the steps they have taken to validate such an approach. The CERDM also took account of any steps that have been taken within the health network that were brought to its attention. Finally, the CERDM evaluated the options identified based on the following criteria: 1) the safety of health care workers, i.e., the effectiveness of the procedure in reducing pathogen burden, the integrity of the mask after disinfection (filtration efficiency and facepiece fit) and the absence of residual chemical hazard and 2) feasibility, i.e., the availability of disinfection equipment, its performance and the requirements for the procedure (INSPQ, 2020a). These criteria are consistent with those of Health Canada (2020a).
Technologies and equipment approved by Health Canada
Low-temperature sterilizers (hydrogen peroxide plasma or vaporized hydrogen peroxide)
Disinfection of N95 masks in low-temperature sterilizers available in medical device reprocessing departments (MDRDs) is an easily accessible short-term solution that meets our evaluation criteria.
Currently, three manufacturers of low-temperature sterilizers have had their technology approved by Health Canada under the Interim Order applicable to the present pandemic (Health Canada, 2020b) and have issued disinfection instructions:
- Stryker: Sterizone VP4
- ASP: Sterrad 100S, Sterrad NX et Sterrad 100NX
- Steris: V-PRO 1plus, V-PRO maX, V-PRO maX2
Consideration should be given to the fact that these models are possibly already being used for the regular activities of MDRDs. The quantity of N95 masks that can be disinfected in low-temperature sterilizers, while not negligible, is significantly lower than that which could be achieved using other devices that can perform large-scale disinfection of N95 masks.
Hydrogen peroxide vaporizer (room disinfection device)
Vaporized hydrogen peroxide is generated by vaporizing an aqueous solution of hydrogen peroxide, which is then diffused into a room by means of a room disinfection device.
The following device was approved under the Interim Order (Health Canada, 2020b):
- Ecolab: Bioquell
This technique is an effective means of disinfecting several masks at the same time. Depending on the characteristics of the device, the size of the room and the operating parameters, this option could theoretically allow for a much higher yield than low-temperature sterilizers. This technology is rarely found at present within the health network.
Disinfection device combining several technologies (UVC, vaporized hydrogen peroxide and ozone)
The following device was approved under the Interim Order (Health Canada, 2020b):
- Clean Works Medical: Clean Flow Health Care Mini
This device, manufactured in Ontario, is used in the agri-food industry and could disinfect up to 800 N95 masks per hour. To our knowledge, this device is not currently found in Québec health care facilities.
Technologies not yet approved by Health Canada
Devices using UVC technology, recommended by ECRI, have applied to Health Canada to be authorized for disinfection of N95 masks.
Options not retained by the CERDM
Heat disinfection (moist or dry) was not retained as an option by the CERDM. In fact, the maximum temperature to which masks can be exposed without affecting their integrity may be insufficient to eliminate certain infectious agents, such as bacterial spores.
Tests conducted in Québec on the Nocospray device, using hydrogen peroxide nebulization, did not enable elimination of the pathogen burden and resulted in an accumulation of silver nitrate in the mask following disinfection cycles. Therefore, this technology was not retained as an option.
In the event of a real shortage, the CERDM recommends following:
- The recommendations of the Comité sur les infections nosocomiales du Québec (CINQ) including that of optimizing the use of N95 masks (INSPQ, 2020 b,c);
- The manufacturers’ instructions for the technologies approved by Health Canada for disinfection of single-use N95 masks under the Interim Order regarding the use of medical devices in relation to COVID-19 (Health Canada, 2020b), as well as the CERDM’s guidelines (INSPQ, 2020d), to develop for the facility an internal disinfection procedure, from the collection of N95 masks up to their storage.
In addition, a number of initiatives within the health network have been reported. The CERDM would like to be informed of these initiatives so it can support facilities and assist in the dissemination of information concerning the options for disinfection of N95 masks.
- CSA Group. Canadian Medical Device Reprocessing. Z314-18. August 2018.
- Food and Drug Administration (FDA). (2020a). Enforcement Policy for Sterilizers, Disinfectant Devices and Air Purifiers During the Coronavirus Disease 2019 (COVID-19) Public Health Emergency, March, 2020.
- Food and Drug Administration (FDA). (2020b). Hinton D.M., Battelle Memorial Institute, March 29, 2020. Retrieved from https://www.fda.gov/media/136529/download
- Institut national de santé publique du Québec (INSPQ), (2020a). CERDM : Évaluation des options de désinfection des protections respiratoires N95 dans le contexte de la pandémie de COVID-19. Retrieved from: https://www.inspq.qc.ca/publications/2971-options-desinfection-n95-covid19
- Institut national de santé publique du Québec (INSPQ), (2020b) Comité des infections nosocomiales du Québec (CINQ). COVID19 : Mesures de prévention et contrôle des infections pour les milieux de soins aigus : recommandations intérimaires. Retrieved from: https://www.inspq.qc.ca/publications/2906-pci-soins-aigus-covid19
- Institut national de santé publique du Québec (INSPQ), (2020c) Comité des infections nosocomiales du Québec (CINQ). Réutilisation des respirateurs N95 lors de la pandémie de la COVID-19 : Avis intérimaire. Retrieved from: https://www.inspq.qc.ca/publications/2918-reutilisation-respirateurs-n95-covid19
- Institut national de santé publique du Québec (INSPQ). (2020d). COVID-19: Interim Guidelines - Collection, Disinfection and Storage Processes for Single-Use N95 Filtering Facepiece Respirators. Retrieved from https://www.inspq.qc.ca/sites/default/files/covid/2965-disinfection-storage-single-use-N95-facepiece-respirators-covid19.pdf
- Health Canada (2020a). Notice – Important Regulatory Considerations for the Reprocessing of Single Use N95 Respirators during the COVID-19 Response. April 8, 2020. Retrieved from https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-devices/activities/announcements/covid19-notice-reprocessing-n95-respirators.html
- Health Canada (2020b). Medical devices for use against coronavirus (COVID-19): List of products authorized under Interim Order. April 15, 2020. Retrieved from https://www.canada.ca/en/health-canada/services/drugs-health-products/covid19-industry/medical-devices/products-authorized-interim-orde.html
1.0 (in French only)
|CERDM||Creation of interim recommandations|
|2.0 (in French only)||2020-04-16||CERDM||
The recommendations below are based on the latest information available at the time of writing. Given that the situation and knowledge about the SARS-CoV-2 virus (COVID-19) are evolving rapidly, the recommendations in this document are subject to change.