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1.
PLoS One ; 17(1): e0257963, 2022.
Article in English | MEDLINE | ID: covidwho-1608831

ABSTRACT

In times of crisis, including the current COVID-19 pandemic, the supply chain of filtering facepiece respirators, such as N95 respirators, are disrupted. To combat shortages of N95 respirators, many institutions were forced to decontaminate and reuse respirators. While several reports have evaluated the impact on filtration as a measurement of preservation of respirator function after decontamination, the equally important fact of maintaining proper fit to the users' face has been understudied. In the current study, we demonstrate the complete inactivation of SARS-CoV-2 and preservation of fit test performance of N95 respirators following treatment with dry heat. We apply scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) measurements, Raman spectroscopy, and contact angle measurements to analyze filter material changes as a consequence of different decontamination treatments. We further compared the integrity of the respirator after autoclaving versus dry heat treatment via quantitative fit testing and found that autoclaving, but not dry heat, causes the fit of the respirator onto the users face to fail, thereby rendering the decontaminated respirator unusable. Our findings highlight the importance to account for both efficacy of disinfection and mask fit when reprocessing respirators to for clinical redeployment.


Subject(s)
COVID-19/prevention & control , Decontamination/methods , Equipment Reuse , N95 Respirators/virology , SARS-CoV-2/physiology , COVID-19/transmission , Equipment and Supplies , Health Personnel , Hot Temperature , Humans , Pandemics
2.
PLoS One ; 16(9): e0255338, 2021.
Article in English | MEDLINE | ID: covidwho-1518352

ABSTRACT

Global shortages of N95 respirators have led to an urgent need of N95 decontamination and reuse methods that are scientifically validated and available world-wide. Although several large scale decontamination methods have been proposed (hydrogen peroxide vapor, UV-C); many of them are not applicable in remote and low-resource settings. Heat with humidity has been demonstrated as a promising decontamination approach, but care must be taken when implementing this method at a grassroots level. Here we present a simple, scalable method to provide controlled humidity and temperature for individual N95 respirators which is easily applicable in low-resource settings. N95 respirators were subjected to moist heat (>50% relative humidity, 65-80°C temperature) for over 30 minutes by placing them in a sealed container immersed in water that had been brought to a rolling boil and removed from heat, and then allowing the containers to sit for over 45 minutes. Filtration efficiency of 0.3-4.99 µm incense particles remained above 97% after 5 treatment cycles across all particle size sub-ranges. This method was then repeated at a higher ambient temperature and humidity in Mumbai, using standard utensils commonly found in South Asia. Similar temperature and humidity profiles were achieved with no degradation in filtration efficiencies after 6 cycles. Higher temperatures (>70°C) and longer treatment times (>40 minutes) were obtained by insulating the outer vessel. We also showed that the same method can be applied for the decontamination of surgical masks. This simple yet reliable method can be performed even without electricity access using any heat source to boil water, from open-flame stoves to solar heating, and provides a low-cost route for N95 decontamination globally applicable in resource-constrained settings.


Subject(s)
COVID-19/prevention & control , Decontamination/methods , Equipment Reuse/statistics & numerical data , Hot Temperature , Humidity , Masks/standards , N95 Respirators/standards , Asia/epidemiology , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Filtration , Humans , SARS-CoV-2
3.
PLoS One ; 16(10): e0258245, 2021.
Article in English | MEDLINE | ID: covidwho-1468167

ABSTRACT

Since the innovation of our new half-piece elastometric respirator, this type of filtering facepiece respirator (FFR) has been used widely in Thailand. Decontamination methods including ultraviolet C (UVC) germicidal irradiation and 70% alcohol have been implemented to decontaminate these respirators. We then examined the inactivation potential of different decontamination processes on porcine epidemic diarrhea virus (PEDV) and numerous bacterial strains, most of which were skin-derived. To enable rigorous integrity of the masks after repeated decontamination processes, fit tests by the Bitrex test, tensile strength and elongation at break were also evaluated. Our results showed that UVC irradiation at a dose of 3 J/cm2 can eradicate bacteria after 60 min and viruses after 10 min. No fungi were found on the mask surface before decontamination. The good fit test results, tensile strength and elongation at break were still maintained after multiple cycles of decontamination. No evidence of physical degradation was found by gross visual inspection. Alcohol (70%) is also an easy and effective way to eradicate microorganisms on respirators. As the current pandemic is expected to continue for months to years, the need to supply adequate reserves of personnel protective equipment (PPE) and develop effective PPE reprocessing methods is crucial. Our studies demonstrated that the novel silicone mask can be safely reprocessed and decontaminated for many cycles by UVC irradiation, which will help ameliorate the shortage of important protective devices in the COVID-19 pandemic era.


Subject(s)
COVID-19 , Decontamination/methods , Respiratory Protective Devices , Ultraviolet Rays , Ventilators, Mechanical , Humans , Pandemics , Silicones
4.
Sci Rep ; 11(1): 20341, 2021 10 13.
Article in English | MEDLINE | ID: covidwho-1467127

ABSTRACT

During public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of "on-N95" UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.


Subject(s)
Decontamination/methods , N95 Respirators/statistics & numerical data , SARS-CoV-2/radiation effects , COVID-19/metabolism , COVID-19/prevention & control , COVID-19/transmission , Dose-Response Relationship, Radiation , Equipment Reuse , Humans , Masks , N95 Respirators/virology , Pandemics , Radiometry/methods , SARS-CoV-2/pathogenicity , Ultraviolet Rays , Virus Inactivation
5.
PLoS One ; 16(10): e0258336, 2021.
Article in English | MEDLINE | ID: covidwho-1463315

ABSTRACT

Decontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. Although the United States Center for Disease Control has identified Ultraviolet-C irradiation as one of the most promising methods for N95 decontamination, very few studies have evaluated the efficacy of Ultraviolet-C for SARS-CoV-2 inactivation. In addition, most decontamination studies are performed using mask coupons that do not recapitulate the complexity of whole masks. We sought to directly evaluate the efficacy of Ultraviolet-C mediated inactivation of SARS-CoV-2 on N95 respirators. To that end we created a portable UV-C light-emitting diode disinfection chamber and tested decontamination of SARS-CoV-2 at different sites on two models of N95 respirator. We found that decontamination efficacy depends on mask model, material and location of the contamination on the mask. Our results emphasize the need for caution when interpreting efficacy data of UV-C decontamination methods.


Subject(s)
Decontamination , Disinfection , Masks , N95 Respirators , Ultraviolet Rays , Decontamination/instrumentation , Decontamination/methods , Disinfection/instrumentation , Disinfection/methods , Equipment Reuse
6.
Antimicrob Resist Infect Control ; 10(1): 144, 2021 10 11.
Article in English | MEDLINE | ID: covidwho-1463271

ABSTRACT

BACKGROUND: With the current COVID-19 pandemic, many healthcare facilities have been lacking a steady supply of filtering facepiece respirators. To better address this challenge, the decontamination and reuse of these respirators is a strategy that has been studied by an increasing number of institutions during the COVID-19 pandemic. METHODS: We conducted a systematic literature review in PubMed, PubMed Central, Embase, and Google Scholar. Studies were eligible when (electronically or in print) up to 17 June 2020, and published in English, French, German, or Spanish. The primary outcome was reduction of test viruses or test bacteria by log3 for disinfection and log6 for sterilization. Secondary outcome was physical integrity (fit/filtration/degradation) of the respirators after reprocessing. Materials from the grey literature, including an unpublished study were added to the findings. FINDINGS: Of 938 retrieved studies, 35 studies were included in the analysis with 70 individual tests conducted. 17 methods of decontamination were found, included the use of liquids (detergent, benzalkonium chloride, hypochlorite, or ethanol), gases (hydrogen peroxide, ozone, peracetic acid or ethylene oxide), heat (either moist with or without pressure or dry heat), or ultra violet radiation (UVA and UVGI); either alone or in combination. Ethylene oxide, gaseous hydrogen peroxide (with or without peracetic acid), peracetic acid dry fogging system, microwave-generated moist heat, and steam seem to be the most promising methods on decontamination efficacy, physical integrity and filtration capacity. INTERPRETATION: A number of methods can be used for N95/FFP2 mask reprocessing in case of shortage, helping to keep healthcare workers and patients safe. However, the selection of disinfection or sterilization methods must take into account local availability and turnover capacity as well as the manufacturer; meaning that some methods work better on specific models from specific manufacturers. SYSTEMATIC REGISTRATION NUMBER: CRD42020193309.


Subject(s)
COVID-19/prevention & control , Decontamination/methods , Equipment Reuse , N95 Respirators , Humans
7.
Sci Rep ; 11(1): 19888, 2021 10 06.
Article in English | MEDLINE | ID: covidwho-1454817

ABSTRACT

To cope with the shortage of filtering facepiece respirators (FFRs) during the coronavirus (COVID-19) pandemic, healthcare institutions were forced to reuse FFRs after applying different decontamination methods including gamma-irradiation (GIR). The aim of this study was to evaluate the effect of GIR on the filtration efficiency (FE) of FFRs and on SARS-CoV-2 detection. The FE of 2 FFRs types (KN95 and N95-3 M masks) was assessed at different particle sizes (0.3-5 µm) following GIR (0-15 kGy) delivered at either typical (1.65 kGy/h) or low (0.5088 kGy/h) dose rates. The detection of two SARS-CoV-2 RNA genes (E and RdRp4) following GIR (0-50 kGy) was carried out using RT-qPCR assay. Both masks showed an overall significant (P < 0.001) reduction in FE with increased GIR doses. No significant differences were observed between GIR dose rates on FE. The GIR exhibited significant increases (P ≤ 0.001) in the cycle threshold values (ΔCt) of both genes, with no detection following high doses. In conclusion, complete degradation of SARS-CoV-2 RNA can be achieved by high GIR (≥ 30 kGy), suggesting its potential use in FFRs decontamination. However, GIR exhibited adverse effects on FE in dose- and particle size-dependent manners, rendering its use to decontaminate FFRs debatable.


Subject(s)
COVID-19/virology , Decontamination/methods , Masks , SARS-CoV-2/isolation & purification , Ventilators, Mechanical , COVID-19/prevention & control , COVID-19/transmission , Filtration , Gamma Rays , Humans , Particle Size
8.
Sci Rep ; 11(1): 19750, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1454812

ABSTRACT

N95 filtering facepiece respirators (FFRs) are essential for the protection of healthcare professionals and other high-risk groups against Coronavirus Disease of 2019 (COVID-19). In response to shortages in FFRs during the ongoing COVID-19 pandemic, the Food and Drug Administration issued an Emergency Use Authorization permitting FFR decontamination and reuse. However, although industrial decontamination services are available at some large institutions, FFR decontamination is not widely accessible. To be effective, FFR decontamination must (1) inactivate the virus; (2) preserve FFR integrity, specifically fit and filtering capability; and (3) be non-toxic and safe. Here we identify and test at-home heat-based methods for FFR decontamination that meet these requirements using common household appliances. Our results identify potential protocols for simple and accessible FFR decontamination, while also highlighting unsuitable methods that may jeopardize FFR integrity.


Subject(s)
Decontamination/methods , N95 Respirators , COVID-19/prevention & control , COVID-19/virology , Hot Temperature , Humans , SARS-CoV-2/isolation & purification , Time Factors
9.
Sci Rep ; 11(1): 18316, 2021 09 15.
Article in English | MEDLINE | ID: covidwho-1412847

ABSTRACT

Shortages of personal protective equipment for use during the SARS-CoV-2 pandemic continue to be an issue among health-care workers globally. Extended and repeated use of N95 filtering facepiece respirators without adequate decontamination is of particular concern. Although several methods to decontaminate and re-use these masks have been proposed, logistic or practical issues limit adoption of these techniques. In this study, we propose and validate the use of the application of moist heat (70 °C with humidity augmented by an open pan of water) applied by commonly available hospital (blanket) warming cabinets to decontaminate N95 masks. This report shows that a variety of N95 masks can be repeatedly decontaminated of SARS-CoV-2 over 6 h moist heat exposure without compromise of their filtering function as assessed by standard fit and sodium chloride aerosol filtration efficiency testing. This approached can easily adapted to provide point-of-care N95 mask decontamination allowing for increased practical utility of mask recycling in the health care setting.


Subject(s)
Decontamination/methods , N95 Respirators/virology , SARS-CoV-2/physiology , Equipment Reuse , Hospitals , Humans , Humidity , Point-of-Care Systems , Time Factors , Virus Inactivation
10.
PLoS One ; 16(9): e0255148, 2021.
Article in English | MEDLINE | ID: covidwho-1405336

ABSTRACT

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.


Subject(s)
Decontamination/methods , Equipment Reuse/standards , Masks/virology , COVID-19/prevention & control , Hot Temperature , Humans , Humidity , SARS-CoV-2
11.
Photochem Photobiol Sci ; 20(7): 955-965, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1384775

ABSTRACT

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log10 reduction of Geobacillus stearothermophilus spores) on FFRs and viruses (> 4 log10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log10 reduction of Vesicular stomatitis virus) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered.


Subject(s)
COVID-19 , Decontamination/methods , N95 Respirators/microbiology , N95 Respirators/virology , Bacteria/drug effects , Bacteria/isolation & purification , Bacteria/radiation effects , COVID-19/epidemiology , Disinfection/methods , Ethanol/pharmacology , Humans , Hydrogen Peroxide/pharmacology , Microwaves , Ultraviolet Rays , Viruses/drug effects , Viruses/isolation & purification , Viruses/radiation effects
12.
PLoS One ; 16(5): e0251817, 2021.
Article in English | MEDLINE | ID: covidwho-1388915

ABSTRACT

The transmission of SARS-CoV-2 through contact with contaminated surfaces or objects is an important form of transmissibility. Thus, in this study, we evaluated the performance of a disinfection chamber designed for instantaneous dispersion of the biocidal agent solution, in order to characterize a new device that can be used to protect individuals by reducing the transmissibility of the disease through contaminated surfaces. We proposed the necessary adjustments in the configuration to improve the dispersion on surfaces and the effectiveness of the developed equipment. Computational Fluid Dynamics (CFD) simulations of the present technology with a chamber having six nebulizer nozzles were performed and validated through qualitative and quantitative comparisons, and experimental tests were conducted using the method Water-Sensitive Paper (WSP), with an exposure to the biocidal agent for 10 and 30 s. After evaluation, a new passage procedure for the chamber with six nozzles and a new configuration of the disinfection chamber were proposed. In the chamber with six nozzles, a deficiency was identified in its central region, where the suspended droplet concentration was close to zero. However, with the new passage procedure, there was a significant increase in wettability of the surface. With the proposition of the chamber with 12 nozzles, the suspended droplet concentration in different regions increased, with an average increase of 266%. The experimental results of the new configuration proved that there was an increase in wettability at all times of exposure, and it was more significant for an exposure of 30 s. Additionally, even in different passage procedures, there were no significant differences in the results for an exposure of 10 s, thereby showing the effectiveness of the new configuration or improved spraying and wettability by the biocidal agent, as well as in minimizing the impact caused by human factor in the performance of the disinfection technology.


Subject(s)
COVID-19/epidemiology , Decontamination/methods , Disinfection/methods , SARS-CoV-2/drug effects , COVID-19/metabolism , COVID-19/transmission , COVID-19/virology , Decontamination/instrumentation , Disinfectants/analysis , Disinfection/instrumentation , Humans , Hydrodynamics , Models, Theoretical , Pandemics , SARS-CoV-2/isolation & purification
13.
PLoS One ; 16(6): e0250854, 2021.
Article in English | MEDLINE | ID: covidwho-1388910

ABSTRACT

The use of personal protective equipment (PPE) has been considered the most effective way to avoid the contamination of healthcare workers by different microorganisms, including SARS-CoV-2. A spray disinfection technology (chamber) was developed, and its efficacy in instant decontamination of previously contaminated surfaces was evaluated in two exposure times. Seven test microorganisms were prepared and inoculated on the surface of seven types of PPE (respirator mask, face shield, shoe, glove, cap, safety glasses and lab coat). The tests were performed on previously contaminated PPE using a manikin with a motion device for exposure to the chamber with biocidal agent (sodium hypochlorite) for 10 and 30s. In 96.93% of the experimental conditions analyzed, the percentage reduction was >99% (the number of viable cells found on the surface ranged from 4.3x106 to <10 CFU/mL). The samples of E. faecalis collected from the glove showed the lowest percentages reduction, with 86.000 and 86.500% for exposure times of 10 and 30 s, respectively. The log10 reduction values varied between 0.85 log10 (E. faecalis at 30 s in glove surface) and 9.69 log10 (E. coli at 10 and 30 s in lab coat surface). In general, E. coli, S. aureus, C. freundii, P. mirabilis, C. albicans and C. parapsilosis showed susceptibility to the biocidal agent under the tested conditions, with >99% reduction after 10 and 30s, while E. faecalis and P. aeruginosa showed a lower susceptibility. The 30s exposure time was more effective for the inactivation of the tested microorganisms. The results show that the spray disinfection technology has the potential for instant decontamination of PPE, which can contribute to an additional barrier for infection control of healthcare workers in the hospital environment.


Subject(s)
COVID-19/prevention & control , Decontamination , Infection Control , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Protective Clothing , Respiratory Protective Devices , SARS-CoV-2 , Bacteria , Bacterial Infections/epidemiology , Bacterial Infections/prevention & control , Bacterial Infections/transmission , COVID-19/epidemiology , COVID-19/transmission , Decontamination/instrumentation , Decontamination/methods , Humans
14.
BMJ Glob Health ; 5(10)2020 10.
Article in English | MEDLINE | ID: covidwho-1388494

ABSTRACT

INTRODUCTION: During pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators. METHOD: Disposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm2 after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10-300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests. RESULTS: No viable phage particles were recovered from any of the respirators after decontamination (log reduction in virus titre >3), and no reduction in chemical or physical properties (SEM, particle penetrations <5%-6%) were observed. Increasing the UVGI dose 10-fold led to chemical alterations of the respirator filtration media (FTIR) but did not affect the physical properties (particle penetration), which was unaltered even at 3000 mJ/cm2 (50 cycles). When respirators had been used by healthcare workers and undergone decontamination, they had particle penetration significantly greater than never donned respirators. CONCLUSION: This decontamination procedure is an attractive method for respirators in case of shortages during a SARS pandemic. A successful implementation requires a careful design and particle penetration performance control tests over the successive reuse cycles.


Subject(s)
Decontamination/methods , Equipment Contamination/prevention & control , Equipment Reuse , Respiratory Protective Devices , Ultraviolet Rays , Betacoronavirus , COVID-19 , Coronavirus Infections/prevention & control , Equipment Failure Analysis , Humans , Infection Control/methods , Materials Testing , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , SARS-CoV-2
16.
PLoS One ; 16(7): e0241734, 2021.
Article in English | MEDLINE | ID: covidwho-1325370

ABSTRACT

Personal protective equipment (PPE) is crucially important to the safety of both patients and medical personnel, particularly in the event of an infectious pandemic. As the incidence of Coronavirus Disease 2019 (COVID-19) increases exponentially in the United States and many parts of the world, healthcare provider demand for these necessities is currently outpacing supply. In the midst of the current pandemic, there has been a concerted effort to identify viable ways to conserve PPE, including decontamination after use. In this study, we outline a procedure by which PPE may be decontaminated using ultraviolet (UV) radiation in biosafety cabinets (BSCs), a common element of many academic, public health, and hospital laboratories. According to the literature, effective decontamination of N95 respirator masks or surgical masks requires UV-C doses of greater than 1 Jcm-2, which was achieved after 4.3 hours per side when placing the N95 at the bottom of the BSCs tested in this study. We then demonstrated complete inactivation of the human coronavirus NL63 on N95 mask material after 15 minutes of UV-C exposure at 61 cm (232 µWcm-2). Our results provide support to healthcare organizations looking for methods to extend their reserves of PPE.


Subject(s)
COVID-19/prevention & control , Containment of Biohazards/methods , Decontamination/methods , Pandemics , SARS-CoV-2/radiation effects , Ultraviolet Rays , COVID-19/transmission , COVID-19/virology , Dose-Response Relationship, Radiation , Equipment Reuse , Health Personnel/education , Humans , Laboratories/organization & administration , Masks/virology , N95 Respirators/virology , Radiometry/statistics & numerical data , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology
17.
Appl Environ Microbiol ; 87(19): e0031421, 2021 09 10.
Article in English | MEDLINE | ID: covidwho-1319372

ABSTRACT

Decontamination helps limit environmental transmission of infectious agents. It is required for the safe reuse of contaminated medical, laboratory, and personal protective equipment, and for the safe handling of biological samples. Heat treatment is a common decontamination method, notably used for viruses. We show that for liquid specimens (here, solution of SARS-CoV-2 in cell culture medium), the virus inactivation rate under heat treatment at 70°C can vary by almost two orders of magnitude depending on the treatment procedure, from a half-life of 0.86 min (95% credible interval [CI] 0.09, 1.77) in closed vials in a heat block to 37.04 min (95% CI 12.64, 869.82) in uncovered plates in a dry oven. These findings suggest a critical role of evaporation in virus inactivation via dry heat. Placing samples in open or uncovered containers may dramatically reduce the speed and efficacy of heat treatment for virus inactivation. Given these findings, we reviewed the literature on temperature-dependent coronavirus stability and found that specimen container types, along with whether they are closed, covered, or uncovered, are rarely reported in the scientific literature. Heat-treatment procedures must be fully specified when reporting experimental studies to facilitate result interpretation and reproducibility, and must be carefully considered when developing decontamination guidelines. IMPORTANCE Heat is a powerful weapon against most infectious agents. It is widely used for decontamination of medical, laboratory, and personal protective equipment, and for biological samples. There are many methods of heat treatment, and methodological details can affect speed and efficacy of decontamination. We applied four different heat-treatment procedures to liquid specimens containing SARS-CoV-2. Our results show that the container used to store specimens during decontamination can substantially affect inactivation rate; for a given initial level of contamination, decontamination time can vary from a few minutes in closed vials to several hours in uncovered plates. Reviewing the literature, we found that container choices and heat treatment methods are only rarely reported explicitly in methods sections. Our study shows that careful consideration of heat-treatment procedure-in particular the choice of specimen container and whether it is covered-can make results more consistent across studies, improve decontamination practice, and provide insight into the mechanisms of virus inactivation.


Subject(s)
Decontamination/methods , Hot Temperature , Personal Protective Equipment/statistics & numerical data , SARS-CoV-2/physiology , Specimen Handling/methods , Virus Inactivation , Decontamination/instrumentation , Reproducibility of Results , Specimen Handling/instrumentation
18.
J Cancer Res Ther ; 17(2): 551-555, 2021.
Article in English | MEDLINE | ID: covidwho-1268377

ABSTRACT

Background: The coronavirus disease 2019 (COVID 19) is a zoonotic viral infection that originated in Wuhan, China, in December 2019. It was declared a pandemic by the World Health Organization shortly thereafter. This pandemic is going to have a lasting impact on the functioning of pathology laboratories due to the frequent handling of potentially infectious samples by the laboratory personnel. To deal with this unprecedented situation, various national and international guidelines have been put forward outlining the precautions to be taken during sample processing from a potentially infectious patient. Purpose: Most of these guidelines are centered around laboratories that are a part of designated COVID 19 hospitals. However, proper protocols need to be in place in all laboratories, irrespective of whether they are a part of COVID 19 hospital or not as this would greatly reduce the risk of exposure of laboratory/hospital personnel. As part of a laboratory associated with a rural cancer hospital which is not a dedicated COVID 19 hospital, we aim to present our institute's experience in handling pathology specimens during the COVID 19 era. Conclusion: We hope this will address the concerns of small to medium sized laboratories and help them build an effective strategy required for protecting the laboratory personnel from risk of exposure and also ensure smooth and optimum functioning of the laboratory services.


Subject(s)
COVID-19/diagnosis , Clinical Laboratory Services/organization & administration , Infection Control/organization & administration , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Tertiary Care Centers/organization & administration , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Cancer Care Facilities/organization & administration , Cancer Care Facilities/standards , Clinical Laboratory Services/standards , Decontamination/methods , Decontamination/standards , Developing Countries , Disinfection/methods , Disinfection/organization & administration , Disinfection/standards , Hospitals, Rural/organization & administration , Hospitals, Rural/standards , Humans , India/epidemiology , Infection Control/standards , Medical Laboratory Personnel/organization & administration , Medical Laboratory Personnel/standards , Pandemics/prevention & control , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity , Specimen Handling/standards , Tertiary Care Centers/standards , Workforce/organization & administration , Workforce/standards
19.
PLoS One ; 16(6): e0253068, 2021.
Article in English | MEDLINE | ID: covidwho-1264227

ABSTRACT

The novel coronavirus, SARS-CoV-2, has spread into a pandemic since its emergence in Wuhan, China in December of 2019. This has been facilitated by its high transmissibility within the human population and its ability to remain viable on inanimate surfaces for an extended period. To address the latter, we examined the effect of simulated sunlight on the viability of SARS-CoV-2 spiked into tissue culture medium or mucus. The study revealed that inactivation took 37 minutes in medium and 107 minutes in mucus. These times-to-inactivation were unexpected since they are longer than have been observed in other studies. From this work, we demonstrate that sunlight represents an effective decontamination method but the speed of decontamination is variable based on the underlying matrix. This information has an important impact on the development of infection prevention and control protocols to reduce the spread of this deadly pathogen.


Subject(s)
COVID-19/virology , Decontamination/methods , Mucus/virology , SARS-CoV-2/radiation effects , Sunlight , Virus Inactivation/radiation effects , Humans , Microbial Viability/radiation effects , SARS-CoV-2/physiology
20.
Antimicrob Resist Infect Control ; 10(1): 83, 2021 05 29.
Article in English | MEDLINE | ID: covidwho-1247602

ABSTRACT

BACKGROUND: With the current SARS-CoV-2 pandemic, many healthcare facilities are lacking a steady supply of masks worldwide. This emergency situation warrants the taking of extraordinary measures to minimize the negative health impact from an insufficient supply of masks. The decontamination, and reuse of healthcare workers' N95/FFP2 masks is a promising solution which needs to overcome several pitfalls to become a reality. AIM: The overall aim of this article is to provide the reader with a quick overview of the various methods for decontamination and the potential issues to be taken into account when deciding to reuse masks. Ultraviolet germicidal irradiation (UVGI), hydrogen peroxide, steam, ozone, ethylene oxide, dry heat and moist heat have all been methods studied in the context of the pandemic. The article first focuses on the logistical implementation of a decontamination system in its entirety, and then aims to summarize and analyze the different available methods for decontamination. METHODS: In order to have a clear understanding of the research that has already been done, we conducted a systematic literature review for the questions: what are the tested methods for decontaminating N95/FFP2 masks, and what impact do those methods have on the microbiological contamination and physical integrity of the masks? We used the results of a systematic review on the methods of microbiological decontamination of masks to make sure we covered all of the recommended methods for mask reuse. To this systematic review we added articles and studies relevant to the subject, but that were outside the limits of the systematic review. These include a number of studies that performed important fit and function tests on the masks but took their microbiological outcomes from the existing literature and were thus excluded from the systematic review, but useful for this paper. We also used additional unpublished studies and internal communication from the University of Geneva Hospitals and partner institutions. RESULTS: This paper analyzes the acceptable methods for respirator decontamination and reuse, and scores them according to a number of variables that we have defined as being crucial (including cost, risk, complexity, time, etc.) to help healthcare facilities decide which method of decontamination is right for them. CONCLUSION: We provide a resource for healthcare institutions looking at making informed decisions about respirator decontamination. This informed decision making will help to improve infection prevention and control measures, and protect healthcare workers during this crucial time. The overall take home message is that institutions should not reuse respirators unless they have to. In the case of an emergency situation, there are some safe ways to decontaminate them.


Subject(s)
COVID-19/prevention & control , Decontamination/methods , Equipment Reuse , N95 Respirators/standards , SARS-CoV-2 , Ethylene Oxide/pharmacology , Health Personnel , Humans , Hydrogen Peroxide/pharmacology , N95 Respirators/virology , SARS-CoV-2/drug effects , SARS-CoV-2/radiation effects , Steam , Ultraviolet Rays
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