Extended use or reuse of single-use surgical masks and filtering face-piece respirators during the coronavirus disease 2019 (COVID-19) pandemic: A rapid systematic review.

BACKGROUND: Shortages of personal protective equipment during the coronavirus disease 2019 (COVID-19) pandemic have led to the extended use or reuse of single-use respirators and surgical masks by frontline healthcare workers. The evidence base underpinning such practices warrants examination. OBJECTIVES: To synthesize current guidance and systematic review evidence on extended use, reuse, or reprocessing of single-use surgical masks or filtering face-piece respirators. DATA SOURCES: We used the World Health Organization, the European Centre for Disease Prevention and Control, the US Centers for Disease Control and Prevention, and Public Health England websites to identify guidance. We used Medline, PubMed, Epistemonikos, Cochrane Database, and preprint servers for systematic reviews. METHODS: Two reviewers conducted screening and data extraction. The quality of included systematic reviews was appraised using AMSTAR-2. Findings were narratively synthesized. RESULTS: In total, 6 guidance documents were identified. Levels of detail and consistency across documents varied. They included 4 high-quality systematic reviews: 3 focused on reprocessing (decontamination) of N95 respirators and 1 focused on reprocessing of surgical masks. Vaporized hydrogen peroxide and ultraviolet germicidal irradiation were highlighted as the most promising reprocessing methods, but evidence on the relative efficacy and safety of different methods was limited. We found no well-established methods for reprocessing respirators at scale. CONCLUSIONS: Evidence on the impact of extended use and reuse of surgical masks and respirators is limited, and gaps and inconsistencies exist in current guidance. Where extended use or reuse is being practiced, healthcare organizations should ensure that policies and systems are in place to ensure these practices are carried out safely and in line with available guidance.

Reconciling human health with the environment while struggling against the COVID-19 pandemic through improved face mask eco-design.

Surgical masks have become critical for protecting human health against the COVID-19 pandemic, even though their environmental burden is a matter of ongoing debate. This study aimed at shedding light on the environmental impacts of single-use (i.e., MD-Type I) versus reusable (i.e., MD-Type IIR) face masks via a comparative life cycle assessment with a cradle-to-grave system boundary. We adopted a two-level analysis using the ReCiPe (H) method, considering both midpoint and endpoint categories. The results showed that reusable face masks created fewer impacts for most midpoint categories. At the endpoint level, reusable face masks were superior to single-use masks, producing scores of 16.16 and 84.20 MPt, respectively. The main environmental impacts of single-use masks were linked to raw material consumption, energy requirements and waste disposal, while the use phase and raw material consumption made the most significant contribution for reusable type. However, our results showed that lower environmental impacts of reusable face masks strongly depend on the use phase since reusable face masks lost their superior performance when the hand wash scenario was tested. Improvement of mask eco-design emerged as another key factor such as using more sustainable raw materials and designing better waste disposal scenarios could significantly lower the environmental impacts.

Elastomeric Respirators for COVID-19 and the Next Respiratory Virus Pandemic: Essential Design Elements.

Respiratory viruses are transmitted via respiratory particles that are emitted when people breath, speak, cough, or sneeze. These particles span the size spectrum from visible droplets to airborne particles of hundreds of nanometers. Barrier face coverings ("cloth masks") and surgical masks are loose-fitting and provide limited protection from airborne particles since air passes around the edges of the mask as well as through the filtering material. Respirators, which fit tightly to the face, provide more effective respiratory protection. Although healthcare workers have relied primarily on disposable filtering facepiece respirators (such as N95) during the COVID-19 pandemic, reusable elastomeric respirators have significant potential advantages for the COVID-19 and future respiratory virus pandemics. However, currently available elastomeric respirators were not designed primarily for healthcare or pandemic use and require further development to improve their suitability for this application. The authors believe that the development, implementation, and stockpiling of improved elastomeric respirators should be an international public health priority.

The properties of hot household hygroscopic materials and their potential use for non-medical facemask decontamination.

The widespread use of facemasks throughout the population is recommended by the WHO to reduce transmission of the SARS-CoV-2 virus. As some regions of the world are facing mask shortages, reuse may be necessary. However, used masks are considered as a potential hazard that may spread and transmit disease if they are not decontaminated correctly and systematically before reuse. As a result, the inappropriate decontamination practices that are commonly witnessed in the general public are challenging management of the epidemic at a large scale. To achieve public acceptance and implementation, decontamination procedures need to be low-cost and simple. We propose the use of hot hygroscopic materials to decontaminate non-medical facemasks in household settings. We report on the inactivation of a viral load on a facial mask exposed to hot hygroscopic materials for 15 minutes. As opposed to recent academic studies whereby decontamination is achieved by maintaining heat and humidity above a given value, a more flexible procedure is proposed here using a slow decaying pattern, which is both effective and easier to implement, suggesting straightforward public deployment and hence reliable implementation by the population.

Performance and impact of disposable and reusable respirators for healthcare workers during pandemic respiratory disease: a rapid evidence review.

OBJECTIVES: To synthesise evidence concerning the range of filtering respirators suitable for patient care and guide the selection and use of different respirator types. DESIGN: Comparative analysis of international standards for respirators and rapid review of their performance and impact in healthcare. DATA SOURCES: Websites of international standards organisations, Medline and Embase, hand-searching of references and citations. STUDY SELECTION: Studies of healthcare workers (including students) using disposable or reusable respirators with a range of designs. We examined respirator performance, clinician adherence and performance, comfort and impact, and perceptions of use. RESULTS: We included standards from eight authorities across Europe, North and South America, Asia and Australasia and 39 research studies. There were four main findings. First, international standards for respirators apply across workplace settings and are broadly comparable across jurisdictions. Second, effective and safe respirator use depends on proper fitting and fit testing. Third, all respirator types carry a burden to the user of discomfort and interference with communication which may limit their safe use over long periods; studies suggest that they have little impact on specific clinical skills in the short term but there is limited evidence on the impact of prolonged wearing. Finally, some clinical activities, particularly chest compressions, reduce the performance of filtering facepiece respirators. CONCLUSION: A wide range of respirator types and models is available for use in patient care during respiratory pandemics. Careful consideration of performance and impact of respirators is needed to maximise protection of healthcare workers and minimise disruption to care.

Deactivation of SARS-CoV-2 with pulsed-xenon ultraviolet light: Implications for environmental COVID-19 control.

OBJECTIVES: Prolonged survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on environmental surfaces and personal protective equipment may lead to these surfaces transmitting this pathogen to others. We sought to determine the effectiveness of a pulsed-xenon ultraviolet (PX-UV) disinfection system in reducing the load of SARS-CoV-2 on hard surfaces and N95 respirators. METHODS: Chamber slides and N95 respirator material were directly inoculated with SARS-CoV-2 and were exposed to different durations of PX-UV. RESULTS: For hard surfaces, disinfection for 1, 2, and 5 minutes resulted in 3.53 log10, >4.54 log10, and >4.12 log10 reductions in viral load, respectively. For N95 respirators, disinfection for 5 minutes resulted in >4.79 log10 reduction in viral load. PX-UV significantly reduced SARS-CoV-2 on hard surfaces and N95 respirators. CONCLUSION: With the potential to rapidly disinfectant environmental surfaces and N95 respirators, PX-UV devices are a promising technology to reduce environmental and personal protective equipment bioburden and to enhance both healthcare worker and patient safety by reducing the risk of exposure to SARS-CoV-2.

Decontaminating N95 Respirators for Reuse in a Hospital Setting.

With the global outbreak of the COVID-19 pandemic, hospitals in Canada and around the world have been forced to consider conservation strategies to ensure continued availability of personal protective equipment (PPE) for healthcare providers. To mitigate critical PPE shortages, Sinai Health System (Sinai Health), a large academic healthcare institution in Canada, has developed and operationalized a standard operating procedure for the collection, decontamination and reuse of N95 respirators and other single-use PPE using a vaporized hydrogen peroxide decontamination method. Sinai Health has incorporated stringent quality assurance steps to ensure that the N95 respirators are successfully decontaminated without deformation and are safe to use.

Microwave- and heat-based decontamination of N95 filtering facepiece respirators: a systematic review.

BACKGROUND: In pandemics such as COVID-19, shortages of personal protective equipment are common. One solution may be to decontaminate equipment such as facemasks for reuse. AIM: To collect and synthesize existing information on decontamination of N95 filtering facepiece respirators (FFRs) using microwave and heat-based treatments, with special attention to impacts on mask function (aerosol penetration, airflow resistance), fit, and physical traits. METHODS: A systematic review (PROSPERO CRD42020177036) of literature available from Medline, Embase, Global Health, and other sources was conducted. Records were screened independently by two reviewers, and data was extracted from studies that reported on effects of microwave- or heat-based decontamination on N95 FFR performance, fit, physical traits, and/or reductions in microbial load. FINDINGS: Thirteen studies were included that used dry/moist microwave irradiation, heat, or autoclaving. All treatment types reduced pathogen load by a log10 reduction factor of at least three when applied for sufficient duration (>30 s microwave, >60 min dry heat), with most studies assessing viral pathogens. Mask function (aerosol penetration <5% and airflow resistance <25 mmH2O) was preserved after all treatments except autoclaving. Fit was maintained for most N95 models, though all treatment types caused observable physical damage to at least one model. CONCLUSIONS: Microwave irradiation and heat may be safe and effective viral decontamination options for N95 FFR reuse during critical shortages. The evidence does not support autoclaving or high-heat (>90°C) approaches. Physical degradation may be an issue for certain mask models, and more real-world evidence on fit is needed.

Process for disinfection of N95 respirators during COVID-19 utilizing sterile processing department: A single center acute care hospital.

During the COVID-19 crisis, disposable N-95 filtering face piece respirators became a critical supply in many health care institutions. Infection preventionists nationwide struggled with ensuring their facilities had personal protective equipment available while utilizing crisis capacity strategies. Many facilities began using US Centers for Disease Control and Prevention and US Food and Drug Administration guidance to disinfect and reprocess N95 respirators for extended use. N95 respirators are collected for all clinical units on a scheduled basis by the sterile processing department (SPD) in individually labeled bins. Bins are checked into SPD and logged into electronic system to track mask volumes by unit. Masks are inspected by SPD team members, packaged in sterile peel packs on the decontamination side and sent to the clean side of the department. Masks are then reprocessed in the appropriate equipment based on the US Food and Drug Administration Emergency Use Authorization guidelines. The facility was able to provide a consistent method of N95 reprocessing throughout the facility. Utilizing an interdisciplinary team to include the operating room, infection preventionist, SPD, and nursing leadership to troubleshoot and identify barriers on a routine basis was key to making the program a success for the many months of the COVID-19 pandemic.

[Reuse process of positive pressure powered air-filter protective hoods].

OBJECTIVE: To establish reuse process of positive pressure powered air-filter protective hoods during coronavirus disease 2019 (COVID-19) epidemic. METHODS: The procedure of pretreatment, storage, recovery, cleaning, disinfection and sterilization process of positive pressure powered air-filter protective hoods, which were used in the treatment of COVID-19 infection patients was established in Central Sterile Supply Department of the hospital. The cleaning and disinfection effects of the protective hoods after treatment were examined by magnifying glass method, residual protein detection method, real-time PCR, and agar pour plate method. RESULTS: Twenty five used protective hoods underwent totally 135 times of washing, disinfecting and sterilizing procedures. After washing, all the protein residue tests and COVID-19 nucleic acid tests showed negative results. After sterilizing, all the protective hoods met sterility requirement. All the tested protective hoods were undamaged after reprocessing. CONCLUSIONS: The established reuse procedures for used positive pressure powered air-filter protective hoods are safe.

Gravity steam reprocessing in healthcare facilities for the reuse of N95 respirators.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has significantly impacted the health of millions of people around the world. The shortage of personal protective equipment, including N95 respirators, in hospital facilities has put frontline healthcare professionals at high risk for contracting this virus. AIM: To develop a reproducible and safe N95 respirator reprocessing method that satisfies all presented regulatory standards and that can be directly implemented by hospitals using existing available equipment. METHODS: A non-toxic gravity steam reprocessing method has been developed for the reuse of N95 respirators consisting of 30 min of steam treatment at 121°C followed by 30 min of heat drying. Samples of model number 1860, 1860s, 1870+, and 9105 N95 respirators were either collected from hospitals (for microbiology testing) or purchased new (for functionality testing), with all functionality tests (i.e. filter efficiency, fit evaluation, and strap integrity) performed at the Centers for Disease Control and Prevention using standard procedures established by the National Institute for Occupational Safety and Health. FINDINGS: All tested models passed the minimum filter efficiency of 95% after three cycles of gravity steam reprocessing. The 1870+ N95 respirator model is the most promising model for reprocessing based on its efficient bacterial inactivation coupled with the maintenance of all other key functional respirator properties after multiple reprocessing steps. CONCLUSIONS: The gravity steam method can effectively reprocess N95 respirators over at least three reprocessing cycles without negatively impacting the functionality requirements set out by regulators. Enabling the reuse of N95 respirators is a crucial tool for managing both the current pandemic and future healthcare crises.

The use of germicidal ultraviolet light, vaporized hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus.

BACKGROUND: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. AIM: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. METHODS: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. FINDINGS: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. CONCLUSION: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.

Decontaminating N95 and SN95 masks with ultraviolet germicidal irradiation does not impair mask efficacy and safety.

Inadequate supply of filtering facepiece respirators (FFRs) for healthcare workers during a pandemic such as the novel coronavirus outbreak (SARS-CoV-2) is a serious public health issue. The aim of this study was to synthesize existing data on the effectiveness of ultraviolet germicidal irradiation (UVGI) for N95 FFR decontamination. A systematic review (PROSPERO CRD42020176156) was conducted on UVGI in N95 FFRs using Embase, Medline, Global Health, Google Scholar, WHO feed, and MedRxiv. Two reviewers independently determined eligibility and extracted predefined variables. Original research reporting on function, decontamination, or mask fit following UVGI were included. Thirteen studies were identified, comprising 54 UVGI intervention arms and 58 N95 models. FFRs consistently maintained certification standards following UVGI. Aerosol penetration averaged 1.19% (0.70-2.48%) and 1.14% (0.57-2.63%) for control and UVGI arms, respectively. Airflow resistance for the control arms averaged 9.79 mm H2O (7.97-11.70 mm H2O) vs 9.85 mm H2O (8.33-11.44 mm H2O) for UVGI arms. UVGI protocols employing a cumulative dose >20,000 J/m2 resulted in a 2-log reduction in viral load. A >3-log reduction was observed in seven UVGI arms using >40,000 J/m2. Impact of UVGI on fit was evaluated in two studies (16,200; 32,400 J/m2) and no evidence of compromise was found. Our findings suggest that further work in this area (or translation to a clinical setting) should use a cumulative UV-C dose of 40,000 J/m2 or greater, and confirm appropriate mask fit following decontamination.

Efficacy and safety of disinfectants for decontamination of N95 and SN95 filtering facepiece respirators: a systematic review.

BACKGROUND: Decontaminating and reusing filtering facepiece respirators (FFRs) for healthcare workers is a potential solution to address inadequate FFR supply during a global pandemic. AIM: The objective of this review was to synthesize existing data on the effectiveness and safety of using chemical disinfectants to decontaminate N95 FFRs. METHODS: A systematic review was conducted on disinfectants to decontaminate N95 FFRs using Embase, Medline, Global Health, Google Scholar, WHO feed, and MedRxiv. Two reviewers independently determined study eligibility and extracted predefined data fields. Original research reporting on N95 FFR function, decontamination, safety, or FFR fit following decontamination with a disinfectant was included. FINDINGS AND CONCLUSION: A single cycle of vaporized hydrogen peroxide (H2O2) successfully removes viral pathogens without affecting airflow resistance or fit, and maintains an initial filter penetration of <5%, with little change in FFR appearance. Residual hydrogen peroxide levels following decontamination were within safe limits. More than one decontamination cycle of vaporized H2O2 may be possible but further information is required on how multiple cycles would affect FFR fit in a real-world setting before the upper limit can be established. Although immersion in liquid H2O2 does not appear to adversely affect FFR function, there is no available data on its ability to remove infectious pathogens from FFRs or its impact on FFR fit. Sodium hypochlorite, ethanol, isopropyl alcohol, and ethylene oxide are not recommended due to safety concerns or negative effects on FFR function.

N95 mask reuse in a major urban hospital: COVID-19 response process and procedure.

BACKGROUND: The shortage of single-use N95 respirator masks (NRMs) during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has prompted consideration of NRM recycling to extend limited stocks by healthcare providers and facilities. AIM: To assess potential reuse via autoclaving of NRMs worn daily in a major urban Canadian hospital. METHODS: NRM reusability was assessed following collection from volunteer staff after 2-8 h use, sterilization by autoclaving and PortaCount fit testing. A workflow was developed for reprocessing hundreds of NRMs daily. FINDINGS: Used NRMs passed fit testing after autoclaving once, with 86% passing a second reuse/autoclave cycle. A separate cohort of used masks pre-warmed before autoclaving passed fit testing. To recycle 200-1000 NRMs daily, procedures for collection, sterilization and re-distribution were developed to minimize particle aerosolization risk during NRM handling, to reject NRM showing obvious wear, and to promote adoption by staff. NRM recovery ranged from 49% to 80% across 12 collection cycles. CONCLUSION: Reuse of NRMs is feasible in major hospitals and other healthcare facilities. In sharp contrast to studies of unused NRMs passing fit testing after 10 autoclave cycles, we show that daily wear substantially reduces NRM fit, limiting reuse to a single cycle, but still increasing NRM stocks by ∼66%. Such reuse requires development of a comprehensive plan that includes communication across staffing levels, from front-line workers to hospital administration, to increase the collection, acceptance of and adherence to sterilization processes for NRM recovery.

[Masks as personal protective equipment in the COVID-19 pandemic: How, when and which should be used]. / Mascarillas como equipo de protección individual durante la pandemia de COVID-19: cómo, cuándo y cuáles deben utilizarse.

BACKGROUND AND OBJECTIVE: In the COVID-19 pandemic, the demand of masks has been increased by health professionals and the general population. In this context, it is necessary to summarize the features and indications of the different types of masks. MATERIAL AND METHODS: To consult and to compile the different recommendations disseminated by prestigious institutions such as the World Health Organization, the European Center for Disease Prevention, the Center for Evidence-Based Medicine, or the Ministry of Health of the Government of Spain has been reviewed. RESULTS: The institutions consulted recommend reserving FFP respirators for healthcare workers, especially when carrying out aerosol-generating procedures (AGPs) (minimum FFP2 protection) and consider some reutilization systems during times of scarcity. The use of surgical masks is recommended to professionals who do not perform AGPs and to the symptomatic population but exist variations in its indications intended for the general healthy population. CONCLUSION: In the context of shortage of personal protective equipment due to the COVID-19 pandemic, a prioritization and rationalization of the use of each type of mask should be established according to the user and the activity performed.

Efficacy and safety of decontamination for N95 respirator reuse: a systematic literature search and narrative synthesis.

PURPOSE: Under times of supply chain stress, the availability of some medical equipment and supplies may become limited. The current pandemic involving severe acute respiratory syndrome coronavirus 2 has highlighted limitations to the ordinary provision of personal protective equipment (PPE). For perioperative healthcare workers, N95 masks provide a stark example of PPE in short supply necessitating the creation of scientifically valid protocols for their decontamination and reuse. METHODS: We performed a systematic literature search of MEDLINE, Embase, Cochrane CENTRAL databases, and ClinicalTrials.gov to identify peer-reviewed articles related to N95 mask decontamination and subsequent testing for the integrity of mask filtration and facial seal. To expand this search, we additionally surveyed the official statements from key health agencies, organizations, and societies for relevant citations. RESULTS: Our initial database search resulted in five articles that met inclusion criteria, with 26 articles added from the expanded search. Our search did not reveal any relevant randomized clinical trials or cohort studies. We found that moist mask heating (65-80°C at 50-85% relative humidity for 20-30 min) and vaporous hydrogen peroxide treatment were supported by the literature to provide consistent viral decontamination without compromising mask seal and filtration efficiency. Other investigated decontamination methods lacked comprehensive scientific evidence for all three of these key criteria. CONCLUSIONS: N95 mask reprocessing using either moist heat or vaporous hydrogen peroxide is recommended to ensure healthcare worker safety.

RéSUMé: OBJECTIF: Lorsque les chaînes d'approvisionnement sont mises sous pression, la disponibilité de certains équipements et fournitures médicaux pourrait devenir restreinte. La pandémie actuelle du syndrome respiratoire aigu sévère du coronavirus 2 a mis en lumière les limites de l'approvisionnement usuel des équipements de protection individuelle (EPI). Pour les travailleurs de la santé périopératoires, les masques N95 sont un exemple frappant d'EPI pouvant rapidement venir à manquer et nécessitant l'élaboration de protocoles scientifiquement rigoureux pour leur décontamination et leur réutilisation. MéTHODE: Nous avons réalisé une recherche de littérature systématique dans les bases de données MEDLINE, Embase, Cochrane CENTRAL et sur ClinicalTrials.gov afin d'identifier les articles révisés par les pairs portant sur la décontamination des masques N95 et les tests subséquents pour vérifier l'intégrité de la filtration du masque et son étanchéité sur le visage. Afin d'étendre notre recherche, nous avons également passé en revue les énoncés officiels émanant des agences de santé, ainsi que des organismes et sociétés médicales majeurs pour en extraire les citations pertinentes. RéSULTATS: Notre recherche initiale des bases de données nous a permis d'extraire cinq articles respectant nos critères d'inclusion, et 26 articles ont été ajoutés à la suite de notre recherche étendue. Notre recherche n'a pas découvert d'études cliniques randomisées ou d'études de cohorte pertinentes. Nous avons observé que la décontamination du masque par chaleur humide (65­80°C à une humidité relative de 50­85 % pendant 20-30 min) et le traitement par vapeur de peroxyde d'hydrogène constituaient les deux mesures endossées par la littérature. En effet, ces modalités offrent une décontamination virale constante sans pour autant compromettre l'étanchéité du masque ou son efficacité de filtration. Les autres méthodes de décontamination étudiées ne possédaient pas de données probantes scientifiques exhaustives quant à ces trois critères clés. CONCLUSION: Le retraitement des masques N95 à l'aide de chaleur humide ou de vapeur de peroxyde d'oxygène est recommandé pour assurer la sécurité des travailleurs de la santé.

Decontamination interventions for the reuse of surgical mask personal protective equipment: a systematic review.

BACKGROUND: The high demand for personal protective equipment during the novel coronavirus outbreak has prompted the need to develop strategies to conserve supply. Little is known regarding decontamination interventions to allow for surgical mask reuse. AIM: To identify and synthesize data from original research evaluating interventions to decontaminate surgical masks for the purpose of reuse. METHODS: MEDLINE, Embase, CENTRAL, Global Health, the WHO COVID-19 database, Google Scholar, DisasterLit, preprint servers, and prominent journals from inception to April 8th, 2020, were searched for prospective original research on decontamination interventions for surgical masks. Citation screening was conducted independently in duplicate. Study characteristics, interventions, and outcomes were extracted from included studies by two independent reviewers. Outcomes of interest included impact of decontamination interventions on surgical mask performance and germicidal effects. FINDINGS: Seven studies met eligibility criteria: one evaluated the effects of heat and chemical interventions applied after mask use on mask performance, and six evaluated interventions applied prior to mask use to enhance antimicrobial properties and/or mask performance. Mask performance and germicidal effects were evaluated with heterogeneous test conditions. Safety outcomes were infrequently evaluated. Mask performance was best preserved with dry heat decontamination. Good germicidal effects were observed in salt-, N-halamine-, and nanoparticle-coated masks. CONCLUSION: There is limited evidence on the safety or efficacy of surgical mask decontamination. Given the heterogeneous methods used in studies to date, we are unable to draw conclusions on the most efficacious and safe intervention for decontaminating surgical masks.