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1.
Sci Rep ; 11(1): 24490, 2021 12 29.
Article in English | MEDLINE | ID: covidwho-1594104

ABSTRACT

During the first wave of Covid-19 infections in Germany in April 2020, clinics reported a shortage of filtering face masks with aerosol retention> 94% (FFP2 & 3, KN95, N95). Companies all over the world increased their production capacities, but quality control of once-certified materials and masks came up short. To help identify falsely labeled masks and ensure safe protection equipment, we tested 101 different batches of masks in 993 measurements with a self-made setup based on DIN standards. An aerosol generator provided a NaCl test aerosol which was applied to the mask. A laser aerosol spectrometer measured the aerosol concentration in a range from 90 to 500 nm to quantify the masks' retention. Of 101 tested mask batches, only 31 batches kept what their label promised. Especially in the initial phase of the pandemic in Germany, we observed fluctuating mask qualities. Many batches show very high variability in aerosol retention. In addition, by measuring with a laser aerosol spectrometer, we were able to show that not all masks filter small and large particles equally well. In this study we demonstrate how important internal and independent quality controls are, especially in times of need and shortage of personal protection equipment.


Subject(s)
COVID-19/prevention & control , COVID-19/transmission , Masks/statistics & numerical data , Aerosols , Filtration/instrumentation , Germany , Humans , Masks/standards , Masks/trends , N95 Respirators/standards , N95 Respirators/statistics & numerical data , Occupational Exposure/prevention & control , Pandemics/prevention & control , Personal Protective Equipment/standards , Quality Control , Respiratory Protective Devices/standards , SARS-CoV-2/pathogenicity
2.
Int J Environ Res Public Health ; 18(24)2021 12 17.
Article in English | MEDLINE | ID: covidwho-1580729

ABSTRACT

Since the onset of the coronavirus disease 2019 pandemic, wearing facemasks has become more important for healthcare workers. This study aimed to investigate and compare the influence of wearing N95 respirators and surgical masks for 8 h on physiological and psychological health. Sixty-eight healthcare workers were randomly assigned to the N95 respirator or surgical mask groups. Physiological parameters of participants were measured by Tensor Tip MTX at baseline and at the 2nd, 4th, 6th and 8th h of wearing the facemasks. The symptoms after wearing facemasks were also determined via the questionnaire. There were no significant changes in physiological parameters at most time checkpoints in both groups. Significant differences were observed in terms of heart rate at the 8th h, time trends (adjusted difference of least squares means were -8.53 and -2.01), and interaction of time and mask type between the two groups (p-value for interaction was 0.0146). The values of these physiological parameters were within normal ranges. The N95 respirator group had significantly higher incidences of shortness of breath, headache, dizziness, difficulty talking and fatigue that spontaneously resolved. In conclusion, healthcare workers who wore either N95 respirators or surgical masks during an 8 h shift had no obvious harmful effects on physiological and psychological health. Additionally, the N95 respirator group did not show a higher risk than the surgical mask group.


Subject(s)
COVID-19 , Occupational Exposure , Respiratory Protective Devices , Health Personnel , Humans , Masks , N95 Respirators , SARS-CoV-2
3.
PLoS One ; 16(3): e0247575, 2021.
Article in English | MEDLINE | ID: covidwho-1573727

ABSTRACT

INTRODUCTION: The COVID-19 pandemic has led to widespread shortages of N95 respirators and other personal protective equipment (PPE). An effective, reusable, locally-manufactured respirator can mitigate this problem. We describe the development, manufacture, and preliminary testing of an open-hardware-licensed device, the "simple silicone mask" (SSM). METHODS: A multidisciplinary team developed a reusable silicone half facepiece respirator over 9 prototype iterations. The manufacturing process consisted of 3D printing and silicone casting. Prototypes were assessed for comfort and breathability. Filtration was assessed by user seal checks and quantitative fit-testing according to CSA Z94.4-18. RESULTS: The respirator originally included a cartridge for holding filter material; this was modified to connect to standard heat-moisture exchange (HME) filters (N95 or greater) after the cartridge showed poor filtration performance due to flow acceleration around the filter edges, which was exacerbated by high filter resistance. All 8 HME-based iterations provided an adequate seal by user seal checks and achieved a pass rate of 87.5% (N = 8) on quantitative testing, with all failures occurring in the first iteration. The overall median fit-factor was 1662 (100 = pass). Estimated unit cost for a production run of 1000 using distributed manufacturing techniques is CAD $15 in materials and 20 minutes of labor. CONCLUSION: Small-scale manufacturing of an effective, reusable N95 respirator during a pandemic is feasible and cost-effective. Required quantities of reusables are more predictable and less vulnerable to supply chain disruption than disposables. With further evaluation, such devices may be an alternative to disposable respirators during public health emergencies. The respirator described above is an investigational device and requires further evaluation and regulatory requirements before clinical deployment. The authors and affiliates do not endorse the use of this device at present.


Subject(s)
COVID-19/prevention & control , Equipment Design/instrumentation , Filtration/instrumentation , Pandemics/prevention & control , Personal Protective Equipment , Respiratory Protective Devices , Ventilators, Mechanical , Equipment Reuse , Face , Humans , Materials Testing/instrumentation , N95 Respirators , Occupational Exposure/prevention & control , Printing, Three-Dimensional/instrumentation , SARS-CoV-2/pathogenicity
4.
Clin Med (Lond) ; 21(3): e263-e268, 2021 05.
Article in English | MEDLINE | ID: covidwho-1518788

ABSTRACT

BACKGROUND: A qualitative fit test using bitter-tasting aerosols is the commonest way to determine filtering face-piece (FFP) mask leakage. This taste test is subjective and biased by placebo. We propose a cheap, quantitative modification of the taste test by measuring the amount of fluorescein stained filter paper behind the mask using image analysis. METHODS: A bitter-tasting fluorescein solution was aerosolised during mask fit tests, with filter paper placed on masks' inner surfaces. Participants reported whether they could taste bitterness to determine taste test 'pass' or 'fail' results. Filter paper photographs were digitally analysed to quantify total fluorescence (TF). RESULTS: Fifty-six healthcare professionals were fit tested; 32 (57%) 'passed' the taste test. TF between the taste test 'pass' and 'fail' groups was significantly different (p<0.001). A cut-off (TF = 5.0 × 106 units) was determined at precision (78%) and recall (84%), resulting in 5/56 participants (9%) reclassified from 'pass' to 'fail' by the fluorescein test. Seven out of 56 (12%) reclassified from 'fail' to 'pass'. CONCLUSION: Fluorescein is detectable and sensitive at identifying FFP mask leaks. These low-cost adaptations can enhance exiting fit testing to determine 'pass' and 'fail' groups, protecting those who 'passed' the taste test but have high fluorescein leak, and reassuring those who 'failed' the taste test despite having little fluorescein leak.


Subject(s)
Occupational Exposure , Respiratory Protective Devices , Cost-Benefit Analysis , Fluorescein , Humans , Point-of-Care Systems
5.
Rev. latinoam. enferm. (Online) ; 29: e3492, 2021. graf
Article in English | LILACS (Americas) | ID: covidwho-1503986

ABSTRACT

Objective: to analyze the scientific evidence available on the different reprocessing methods and the necessary conditions for reuse of the N95 face respirator mask or equivalent. Method: an integrative literature review. The PICO strategy was used to elaborate the question. The search was conducted in four databases: PubMed, SciVerse Scopus, WebofScience and EMBASE, considering any period of time. Results: a total of 32 studies were included from the 561 studies identified, and they were presented in two categories: "Conditions for reuse" and "Reprocessing the masks". Of the evaluated research studies, seven(21.8%) addressed the reuse of the N95 face respirator mask or equivalent and 25(78.1%) evaluated different reprocessing methods, namely: ultraviolet germicidal irradiation(14); hydrogen peroxide(8); vapor methods(14); using dry heat(5) and chemical methods(sodium hypochlorite[6], ethanol[4] and sodium chloride with sodium bicarbonate and dimethyldioxirane[1]). We emphasize that different methods were used in one same article. Conclusion: no evidence was found to support safe reprocessing of face respirator masks. In addition, reuse is contraindicated due to the risk of self-contamination and inadequate sealing.


Objetivo: analizar la evidencia científica disponible sobre los diferentes métodos de reprocesamiento y las condiciones necesarias para la reutilización de una mascarilla respiratoria facial N95 o equivalente. Método: revisión integradora de la literatura. Para elaborar la pregunta se utilizó la estrategia PICO. La búsqueda se realizó en cuatro bases de datos PubMed, Sci Verse Scopus, Web of Science y EMBASE sin límite de tiempo. Resultados: de los 561 estudios identificados 32 fueron incluidos y presentados en dos categorías: "condiciones de reutilización" y "reprocesamiento de mascarillas". De las investigaciones evaluadas, siete (21,8%) abordaron la reutilización de la mascarilla respiratoria facial N95 o equivalente y 25 (78,1%) evaluaron diferentes métodos de reprocesamiento: irradiación germicida ultravioleta (14); peróxido de hidrógeno (8); métodos de vapor (14); uso de calor seco (5) y métodos químicos hipoclorito de sodio (6), etanol (4) y cloruro de sodio con bicarbonato de sodio y dimetildioxirano (1). Cabe destacar que en un mismo artículo se utilizaron métodos diferentes. Conclusión: no se encontró evidencia que apoye el reprocesamiento seguro de las mascarillas respiratorias. Además, la reutilización está contraindicada debido al riesgo de autocontaminación y sellado inadecuado.


Objetivo: analisar as evidências científicas disponíveis sobre os diferentes métodos de reprocessamento e as condições necessárias para reuso de máscara respiratória facial do tipo N95 ou equivalente. Método: revisão integrativa da literatura. Para elaboração da questão foi utilizada a estratégia PICO. A busca ocorreu em quatro bases de dados PubMed, Sci Verse Scopus, Web of Science e EMBASE considerando qualquer período de tempo. Resultados: foram incluídos 32 estudos dos 561 identificados e apresentados em duas categorias: "condições para reuso" e "reprocessamento das máscaras". Das pesquisas avaliadas, sete (21,8%) abordaram o reuso da máscara respiratória facial do tipo N95 ou equivalente e 25 (78,1%) avaliaram diferentes métodos de reprocessamento: irradiação germicida ultravioleta (14); peróxido de hidrogênio (8); métodos a vapor (14); utilização do calor seco (5) e métodos químicos (hipoclorito de sódio (6), etanol (4) e cloreto de sódio com bicarbonato de sódio e dimetildioxirano (1). Destacamos que um mesmo artigo utilizou diferentes métodos. Conclusão: não foram encontradas evidências que sustentam o reprocessamento seguro de máscaras respiratórias faciais. Ainda, o reuso é contraindiciado devido ao risco de autocontaminação e vedação inadequada.


Subject(s)
Respiratory Protective Devices , Coronavirus Infections , Facial Masks , Pandemics , Personal Protective Equipment
6.
ACS Appl Bio Mater ; 4(11): 7921-7931, 2021 11 15.
Article in English | MEDLINE | ID: covidwho-1500415

ABSTRACT

The advent of COVID-19 pandemic has made it necessary to wear masks across populations. While the N95 mask offers great performance against airborne infections, its multilayered sealed design makes it difficult to breathe for a longer duration of use. The option of using highly breathable cloth or silk masks especially for a large populace is fraught with the danger of infection. As a normal cloth or silk mask absorbs airborne liquid, it can be a source of plausible infection. We demonstrate the chemical modification of one such mask, Eri silk, to make it hydrophobic (contact angle of water is 143.7°), which reduces the liquid absorption capacity without reducing the breathability of the mask significantly. The breathability reduces only 22% for hydrophobic Eri silk compared to the pristine Eri silk, whereas N95 shows a 59% reduction of breathability. The modified hydrophobic silk can repel the incoming aqueous liquid droplets without wetting the surface. The results indicate that a multilayered modified silk mask to make it hydrophobic can be an affordable and breathable alternative to the N95 mask.


Subject(s)
COVID-19/prevention & control , Masks , Nanostructures/chemistry , Breath Tests , COVID-19/virology , Humans , Hydrophobic and Hydrophilic Interactions , Porosity , Respiratory Protective Devices/virology , SARS-CoV-2/isolation & purification , Silanes/chemistry , Silk/chemistry
7.
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
8.
Sci Rep ; 11(1): 19910, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462025

ABSTRACT

Face masks are a primary preventive measure against airborne pathogens. Thus, they have become one of the keys to controlling the spread of the COVID-19 virus. Common examples, including N95 masks, surgical masks, and face coverings, are passive devices that minimize the spread of suspended pathogens by inserting an aerosol-filtering barrier between the user's nasal and oral cavities and the environment. However, the filtering process does not adapt to changing pathogen levels or other environmental factors, which reduces its effectiveness in real-world scenarios. This paper addresses the limitations of passive masks by proposing ADAPT, a smart IoT-enabled "active mask". This wearable device contains a real-time closed-loop control system that senses airborne particles of different sizes near the mask by using an on-board particulate matter (PM) sensor. It then intelligently mitigates the threat by using mist spray, generated by a piezoelectric actuator, to load nearby aerosol particles such that they rapidly fall to the ground. The system is controlled by an on-board micro-controller unit that collects sensor data, analyzes it, and activates the mist generator as necessary. A custom smartphone application enables the user to remotely control the device and also receive real-time alerts related to recharging, refilling, and/or decontamination of the mask before reuse. Experimental results on a working prototype confirm that aerosol clouds rapidly fall to the ground when the mask is activated, thus significantly reducing PM counts near the user. Also, usage of the mask significantly increases local relative humidity levels.


Subject(s)
COVID-19/prevention & control , Inhalation Exposure/prevention & control , Masks , Particulate Matter/isolation & purification , Respiratory Protective Devices , SARS-CoV-2/isolation & purification , Aerosols/isolation & purification , Air Microbiology , Equipment Design , Filtration/instrumentation , Humans , Mobile Applications , Particle Size , Smart Materials/chemistry , Smartphone
9.
10.
BMC Infect Dis ; 21(1): 712, 2021 Jul 29.
Article in English | MEDLINE | ID: covidwho-1394421

ABSTRACT

BACKGROUND: The COVID-19 pandemic has severely disrupted supply chains for many types of Personal Protective Equipment (PPE), particularly surgical N95 filtering facepiece respirators (FFRs; "masks"). As a consequence, an Emergency Use Authorization (EUA) from the FDA has allowed use of industrial N95 respirators and importation of N95-type masks manufactured to international standards; these include KN95 masks from China and FFP2 masks from the European Union. METHODS: We conducted a survey of masks in the inventory of major academic medical centers in Boston, MA to determine provenance and manufacturer or supplier. We then assembled a testing apparatus at a university laboratory and performed a modified test of filtration performance using KCl and ambient particulate matter on masks from hospital inventories; an accompanying website shows how to build and use the testing apparatus. RESULTS: Over 100 different makes and models of traditional and nontraditional filtering facepiece respirators (N95-type masks) were in the inventory of surveyed U.S. teaching hospitals as opposed to 2-5 models under normal circumstances. A substantial number of unfamiliar masks are from unknown manufacturers. Many are not correctly labelled and do not perform to accepted standards and a subset are obviously dangerous; many of these masks are likely to be counterfeit. Due to the absence of publicly available information on mask suppliers and inconsistent labeling of KN95 masks, it is difficult to distinguish between legitimate and counterfeit products. CONCLUSIONS: Many FFRs available for procurement during the COVID-19 pandemic do not provide levels of fit and filtration similar to those of N95 masks and are not acceptable for use in healthcare settings. Based on these results, and in consultation with occupational health officers, we make six recommendations to assist end users in acquiring legitimate products. Institutions should always assess masks from non-traditional supply chains by checking their markings and manufacturer information against data provided by NIOSH and the latest FDA EUA Appendix A. In the absence of verifiable information on the legitimacy of mask source, institutions should consider measuring mask fit and filtration directly. We also make suggestions for regulatory agencies regarding labeling and public disclosure aimed at increasing pandemic resilience.


Subject(s)
COVID-19 , Occupational Exposure , Respiratory Protective Devices , Humans , Masks , Pandemics/prevention & control , SARS-CoV-2 , Ventilators, Mechanical
11.
BMJ Open ; 11(9): e045557, 2021 09 02.
Article in English | MEDLINE | ID: covidwho-1394106

ABSTRACT

OBJECTIVE: The COVID-19 pandemic has precipitated widespread shortages of filtering facepiece respirators (FFRs) and the creation and sharing of proposed substitutes (novel designs, repurposed materials) with limited testing against regulatory standards. We aimed to categorically test the efficacy and fit of potential N95 respirator substitutes using protocols that can be replicated in university laboratories. SETTING: Academic medical centre with occupational health-supervised fit testing along with laboratory studies. PARTICIPANTS: Seven adult volunteers who passed quantitative fit testing for small-sized (n=2) and regular-sized (n=5) commercial N95 respirators. METHODS: Five open-source potential N95 respirator substitutes were evaluated and compared with commercial National Institute for Occupational Safety and Health (NIOSH)-approved N95 respirators as controls. Fit testing using the 7-minute standardised Occupational Safety and Health Administration fit test was performed. In addition, protocols that can be performed in university laboratories for materials testing (filtration efficiency, air resistance and fluid resistance) were developed to evaluate alternate filtration materials. RESULTS: Among five open-source, improvised substitutes evaluated in this study, only one (which included a commercial elastomeric mask and commercial HEPA filter) passed a standard quantitative fit test. The four alternative materials evaluated for filtration efficiency (67%-89%) failed to meet the 95% threshold at a face velocity (7.6 cm/s) equivalent to that of a NIOSH particle filtration test for the control N95 FFR. In addition, for all but one material, the small surface area of two 3D-printed substitutes resulted in air resistance that was above the maximum in the NIOSH standard. CONCLUSIONS: Testing protocols such as those described here are essential to evaluate proposed improvised respiratory protection substitutes, and our testing platform could be replicated by teams with similar cross-disciplinary research capacity. Healthcare professionals should be cautious of claims associated with improvised respirators when suggested as FFR substitutes.


Subject(s)
COVID-19 , Occupational Exposure , Respiratory Protective Devices , Adult , Equipment Design , Humans , N95 Respirators , Pandemics/prevention & control , SARS-CoV-2 , United States , Ventilators, Mechanical
12.
Infect Control Hosp Epidemiol ; 42(9): 1150-1152, 2021 09.
Article in English | MEDLINE | ID: covidwho-1387085
14.
Am J Infect Control ; 49(6): 825-835, 2021 06.
Article in English | MEDLINE | ID: covidwho-1384850

ABSTRACT

BACKGROUND: Considering the new SARS-CoV-2 pandemic and the potential scarcity of material resources, the reuse of personal protective equipment such as filtering facepiece respirators (FFRs) for N95 filtering or higher is being discussed, mainly regarding the effectiveness and safety of cleaning, disinfection and sterilization processes. AIM: To analyze the available evidence in the literature on the safety in processing FFRs. METHODS: A systematic review conducted by searching for studies in the following databases: PubMed, CINAHL, LILACS, CENTRAL, EMBASE, Web of Science, and Scopus. RESULTS: Forty studies were included in this review. The disinfectant/sterilizing agents most frequently tested at different concentrations and exposure periods were ultraviolet irradiation, vaporized hydrogen peroxide and steam sterilization. Microbial reduction was assessed in 21 (52.5%) studies. The only disinfectants/sterilizers that did not caused degradation of the material-integrity were alcohol, electric cooker, ethylene oxide, and peracetic acid fogging. Exposure to ultraviolet irradiation or microwave generated-steam resulted in a nonsignificant reduction in filter performance. CONCLUSION: There is a complex relationship between the FFR raw materials and the cycle conditions of the decontamination methods, evidencing the need for validating FFRs by models and manufacturers, as well as the process. Some methods may require additional tests to demonstrate the safety of FFRs for use due to toxicity.


Subject(s)
COVID-19 , Respiratory Protective Devices , Decontamination , Equipment Reuse , Humans , SARS-CoV-2 , Ventilators, Mechanical
15.
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
16.
BMC Res Notes ; 14(1): 115, 2021 Mar 25.
Article in English | MEDLINE | ID: covidwho-1388821

ABSTRACT

OBJECTIVES: To reduce the spread of the infection, especially during aerosol generating procedures, we invented "The Cupola", a shield that creates a mechanical barrier around the patient's head and body. With this pilot study we aimed to assess the effectiveness of an additional layer of protection (The Cupola) developed for providers working in the oropharyngeal region. RESULTS: The mean number of 0.3 µm particles with no Cupola was 3777 (SD: ± 556), with The Cupola was 2068 (SD: ± 1468) and with the Cupola and Drape was 2031 (SD: ± 1108) (p < 0.015). The mean number of 0.5 µm airborne particles with no Cupola was 65 (SD: ± 7), with The Cupola was 29 (SD: ± 28) and with the Cupola and Drape was 28 (SD: ± 23) (p < 0.05). Results showed a significant reduction of aerosols generated during simulated dental procedures when the Cupola was used. The Cupola offers an extra layer of protection in addition to the recommended personal protective equipment.


Subject(s)
COVID-19/prevention & control , Dental Care , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Respiratory Protective Devices , Aerosols , COVID-19/transmission , Health Personnel , Humans , Pilot Projects
17.
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
18.
ACS Nano ; 14(7): 9188-9200, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-1387153

ABSTRACT

Filtration efficiency (FE), differential pressure (ΔP), quality factor (QF), and construction parameters were measured for 32 cloth materials (14 cotton, 1 wool, 9 synthetic, 4 synthetic blends, and 4 synthetic/cotton blends) used in cloth masks intended for protection from the SARS-CoV-2 virus (diameter 100 ± 10 nm). Seven polypropylene-based fiber filter materials were also measured including surgical masks and N95 respirators. Additional measurements were performed on both multilayered and mixed-material samples of natural, synthetic, or natural-synthetic blends to mimic cloth mask construction methods. Materials were microimaged and tested against size selected NaCl aerosol with particle mobility diameters between 50 and 825 nm. Three of the top five best performing samples were woven 100% cotton with high to moderate yarn counts, and the other two were woven synthetics of moderate yarn counts. In contrast to recently published studies, samples utilizing mixed materials did not exhibit a significant difference in the measured FE when compared to the product of the individual FE for the components. The FE and ΔP increased monotonically with the number of cloth layers for a lightweight flannel, suggesting that multilayered cloth masks may offer increased protection from nanometer-sized aerosol with a maximum FE dictated by breathability (i.e., ΔP).


Subject(s)
Coronavirus Infections/prevention & control , Masks/standards , Pandemics/prevention & control , Personal Protective Equipment/standards , Pneumonia, Viral/prevention & control , Respiratory Protective Devices/standards , Textiles/standards , Aerosols/chemistry , Betacoronavirus/pathogenicity , COVID-19 , Filtration , Humans , Masks/virology , Nanoparticles/chemistry , Nanoparticles/virology , Personal Protective Equipment/virology , Respiratory Protective Devices/virology , SARS-CoV-2 , Textiles/adverse effects , Textiles/virology
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