Disinfection Of Personal Protective Equipment Research Articles

Production of singlet oxygen from photosensitizer erythrosine for facile inactivation of coronavirus on mask

The global health crisis caused by the COVID-19 pandemic has led to a surge in demand and use of personal protective equipment (PPE) such as masks, putting great pressure on social production and the environment.It is urgent to find an efficient and non-destructive disinfection method for the safe reuse of PPE. This study proposes a PPE disinfection method that uses erythrosine, a U.S. Food and Drug Administration-approved food dye, as photosensitizer to produce singlet oxygen for virus inactivation, and indicates the completion of disinfection by its photobleaching color change.After spraying 100 μL of 10 μM erythrosine on the surface of the mask for 3 times and light exposure for 25 min, the titer of coronavirus decreased by more than 99.999%, and the color of erythrosine on the mask surface disappeared. In addition, the structure of the mask was intact and the filtration efficiency was maintained at > 95% after 10 cycles of erythrosine treatment.Therefore, this disinfection method can provide at least 10 cycles of reuse with the advantages of high safety and convenient, and the completion of disinfection can be indicated by its photobleaching, which is suitable for hospitals and daily life to reduce the consumption of PPE.

End-user acceptability of personal protective equipment disinfection for potential reuse: a survey of health-care workers in Aotearoa New Zealand

The COVID-19 pandemic has highlighted personal protective equipment (PPE) supply, distribution, and disposal issues worldwide. Calls to conserve PPE stocks and increase supply resulted in the rapid development of potential disinfection methods, with the possibility of improvements in medical waste reduction. However, how receptive health-care workers are to PPE reuse remains unknown. We aimed to examine the views of health-care workers who used PPE during the first COVID-19 wave in Aotearoa New Zealand, in relation to acceptability of PPE disinfection and reuse. In this multi-methods survey, health-care workers in New Zealand, were invited via a multimodal recruitment strategy to complete a survey regarding use of PPE during the first COVID-19 wave. Gender question options were male, female, gender diverse, or prefer not to say. Demographic differences in self-reported PPE reuse and acceptability were examined. The survey included closed (single-response, multi-response, ranking, and Likert-scale questions) and open-text questions. Any open-text comments were analysed with thematic analysis. The survey was built and deployed using Qualtrics software. 1411 health-care workers completed the survey between Oct 7 and Nov 30, 2020. 1397 participants had gender data available (1140 [82%] female and 257 [18%] male) and 995 (74%) of 1347 were of New Zealand European ethnicity. PPE reuse was common and reported by 628 (45%) of the 1411 participants, with 396 (63%) of the 628 reporting reusing PPE multiple times in 1 day. Acceptability of the concept of PPE disinfection for potential reuse was high overall (1196 [85%] of 1411) but varied depending on the type of PPE. Thematic analysis confirmed that PPE reuse was already occurring and respondents recognised the potential benefits of reduced medical wastage and increased PPE supply. Important caveats for consideration included the availability of scientific evidence, level of negotiated risk, and trust in the organisation undertaking PPE disinfection, with clear communication about decontamination processes being crucial to acceptability. PPE reuse occurred frequently during the first wave of COVID-19 in New Zealand. Although support for the disinfection of PPE for reuse was high, the success of any future programmes to reuse PPE will require meaningful engagement and clear communication with health-care workers. Further research into PPE disinfection safety and logistics is warranted, alongside the development of standard operating procedures and clearly communicated policies for the end user, should this more sustainable health-care practice be planned for adoption in certain settings. New Zealand Ministry of Business, Innovation and Employment (COVID-19 Innovation Acceleration Fund) and the Medical Assurance Society Foundation.

Applicability of on-site disinfection of personal protective equipment by ozone gas

On-site disinfection techniques are beneficial during a pandemic when there is a marked shortage of personal protective equipment (PPE), as experienced during the coronavirus disease 2019 outbreak. Ozone gas has been considered an alternative on-site disinfectant during a pandemic because it has antimicrobial activities, can be produced from air by electricity without the need for storage, and can be easily deactivated after use. However, ozone gas might become distributed at the lower layer because it has a larger molecular weight than air.This study aimed to reveal the applicability of ozone gas for the on-site disinfection of PPE. The lockers meant for changing dresses were used as ozone gas exposure boxes, and the distribution of ozone was assayed. Considering that the determined ozone levels were not consistent in the types of ozone analysers, we studied the chemical and biological activities of ozone, which were evenly detected in the locker. The gown in the locker was also uniformly exposed to ozone. Results showed that ozone gas could be used for the on-site disinfection of PPE in a closed box, such as a locker. This finding is valuable during a pandemic when PPE is in short supply.

Efficacy of Dry Heat Treatment against Clostridioides difficile Spores and Mycobacterium tuberculosis on Filtering Facepiece Respirators.

The COVID-19 pandemic has required novel solutions, including heat disinfection of personal protective equipment (PPE) for potential reuse to ensure availability for healthcare and other frontline workers. Understanding the efficacy of such methods on pathogens other than SARS-CoV-2 that may be present on PPE in healthcare settings is key to worker safety, as some pathogenic bacteria are more heat resistant than SARS-CoV-2. We assessed the efficacy of dry heat treatment against Clostridioides difficile spores and Mycobacterium tuberculosis (M. tb) on filtering facepiece respirator (FFR) coupons in two inoculums. Soil load (mimicking respiratory secretions) and deionized water was used for C. difficile, whereas, soil load and PBS and Tween mixture was used for M. tb. Dry heat treatment at 85 °C for 240 min resulted in a reduction equivalent to 6.0-log10 CFU and 7.3-log10 CFU in C. difficile spores inoculated in soil load and deionized water, respectively. Conversely, treatment at 75 °C for 240 min led to 4.6-log10 CFU reductions in both soil load and deionized water. C. difficile inactivation was higher by >1.5-log10 CFU in deionized water as compared to soil load (p < 0.0001), indicating the latter has a protective effect on bacterial spore inactivation at 85 °C. For M. tb, heat treatment at 75 °C for 90 min and 85 °C for 30 min led to 8-log10 reduction with or without soil load. Heat treatment near the estimated maximal operating temperatures of FFR materials (which would readily eliminate SARS-CoV-2) did not achieve complete inactivation of C. difficile spores but was successful against M. tb. The clinical relevance of surviving C. difficile spores when subjected to heat treatment remains unclear. Given this, any disinfection method of PPE for potential reuse must ensure the discarding of any PPE, potentially contaminated with C. difficile spores, to ensure the safety of healthcare workers.

Portable Ultraviolet-C Chambers for Inactivation of SARS-CoV-2

The goal of this project was to create and optimize the performance of portable chambers for reliable ultraviolet (UV) disinfection of personal protective equipment (PPE) and enable its safe reuse. During unforeseen times of high demand for PPE, such as during the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), single-use PPE supply can be quickly depleted. UV radiation has been shown to disinfect materials with high efficacy. This paper reports the design and construction of two 280 nm ultraviolet-C (UV-C) disinfection chambers in the form of portable chambers with 46 cm × 46 cm × 46 cm interior dimensions, one using light-emitting diodes and the other using mercury vapor lamps. This paper summarizes and presents a review of SARS-CoV-2 UV deactivation research during 2020 to 2021. Additionally, this paper discusses efforts to increase the uniformity and overall intensity of the UV-C radiation within the chambers through the installation of a UV-reflective, porous polytetrafluoroethylene (PTFE) material. A calculator prototype was additionally designed to calculate the reduction of SARS-CoV-2 as a result of UV-C disinfection, and the prototype code is presented. The paper describes the selection of UV-C radiation sources for the chambers and the chambers’ mechanical and electrical design, PTFE installation, testing, and safety considerations.

Indications for accurate and appropriate use of personal protective equipment for healthcare professionals. A systematic review.

The speed of the spread of coronavirus disease 2019 (COVID-19) has put enormous pressure on hospitals and other healthcare facilities. This, together with blockages in several countries, has hindered the availability and accessibility of the necessary personal protective equipment (PPE). To identify, systematically evaluate and summarize the available scientific evidence on the efficacy, safety, safe use and reuse of PPE for healthcare professionals, for preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Systematic review of studies analyzing products for disinfecting and enabling reuse of PPE for coronavirus within the evidence-based health program of a federal university in São Paulo (SP), Brazil. A systematic search of the relevant literature was conducted in the PubMed, EMBASE, Cochrane Library, CINAHL, SCOPUS, Web of Science and LILACS databases, for articles published up to November 30, 2020. Ten studies were selected. These analyzed the use of N95, surgical and cotton masks, face shields, flexible enclosures with plastic covers or polycarbonate intubation boxes and plastic curtains; and also PPE disinfection using several substances. Combined use of a face shield with a N95 mask proved to be superior to other associations for protecting healthcare workers. Some products are useful for disinfecting PPE, such as 70% ethanol, 0.1% sodium hypochlorite and a mixture of quaternary ammonium and H2O2, and hydrogen peroxide. Ultraviolet light and dry heat at 70 °C can be used to decontaminate N95 masks. DOI: 10.17605/OSF.IO/4V5FD at the OPENSCIENCE Framework.

Investigating the Photothermal Disinfecting Properties of Light-Activated Silver Nanoparticles

The medicinal applications of noble metal nanomaterials are of considerable interest due to the unique properties they possess. The following contribution will showcase one of these properties, the photothermal effect produced by silver nanoparticles (AgNPs), and show how AgNPs can serve as potential viricidal materials for PPE (i.e., personal protective equipment) disinfection. In the context of the COVID-19 global pandemic, PPE disinfection is critical for addressing the shortfalls in the supply chains that ensure rapid and reliable sources of PPE for both medical professionals and the public. Two AgNP composites were prepared using both photochemical and pulsed laser ablation in liquid techniques. Then, to improve the durability of the NPs’ coating, they were mixed in a commercially available tent protectant solution or with a chitosan suspension. Transmission electron microscopy and spectroscopic analyses of the AgNP/protectant composites present mostly monodisperse, spherical particles of ∼5–10 nm in diameter, dependent on the route of nanoparticle synthesis. Blue light-emitting diodes (LEDs) were utilized to activate the surface plasmon resonance effects of the AgNP-coated materials at ∼400 nm. The resultant photothermal activation produced elevated surface temperatures on the fabrics, up to 150 °C, approaching the ignition temperature of the fabric samples, and well above the threshold required to deactivate the SARS-CoV-2 virus responsible for the COVID-19 pandemic. Photothermal heating was found to be largely dependent on both proximity of the coated sample surface to the LED source and illumination intensity. Furthermore, the rate of temperature increase was determined to be considerably faster than traditional or photothermal heating studies conducted on aqueous nanoparticle colloids, illustrating the efficiency of this methodology. Finally, durability studies of the AgNP/protectant coatings were examined and were found to maintain photothermal activity over long durations of exposure and after a 3-month storage timeframe. A marginal decrease in heating can be noticed following laundering with traditional detergent cleaners, mainly during the first washing cycle. The coating resistance to washing could be improved by the cross linkage of a biodegradable polymer, chitosan.

Safely Returning America to Work Part II: Industry-Specific Guidance.

Safely Returning America to Work Part II: Industry-Specific Guidance.

Modeling the Stability of SARS-CoV-2 on Personal Protective Equipment (PPE)

.We modeled the stability of SARS-CoV-2 on personal protective equipment (PPE) commonly worn in hospitals when carrying out high-risk airway procedures. Evaluated PPE included the visors and hoods of two brands of commercially available powered air purifying respirators, a disposable face shield, and Tyvek coveralls. Following an exposure to 4.3 log10 plaque-forming units (PFUs) of SARS-CoV-2, all materials displayed a reduction in titer of > 4.2 log10 by 72 hours postexposure, with detectable titers at 72 hours varying by material (1.1–2.3 log10 PFU/mL). Our results highlight the need for proper doffing and disinfection of PPE, or disposal, to reduce the risk of SARS-CoV-2 contact or fomite transmission.

Fallacies and Facts Around COVID-19: The Multifaceted Infection.

It has been 5 months since the identification of first cases of coronavirus disease 2019 (COVID-19), however, unveiling clinical characteristics and modes of transmission of the disease is not complete yet. The initially identified clinical sign of COVID-19 was respiratory in nature in the form of pneumonia with possible fatal consequences due to severe acute lung fibrosis. Extrapulmonary symptoms of the disease are now well recognized with involvement of the liver, kidney, and even multisystem organ failure and acute cardiac arrest. Symptoms related to the gastrointestinal tract are particularly interesting and these could represent a mode of transmission requiring more attention from researchers and clinicians. Prevalence of diarrhea, nausea, vomiting, or abdominal discomfort is estimated to be approximately 5%.1 The possible multiple routes of transmission could be explained by the fact that angiotensin converting enzyme 2 protein presents in abundance on lung alveolar epithelial cells and enterocytes of small intestine remarkably.2 During the first days of the disease, a fallacy was distributed mainly through social media. Drinking hot drinks was promoted as a means to eradicate the virus before it goes beyond the pharynx; however, as more studies were conducted, it was revealed that SARS-CoV-2 can withstand temperatures up to 56°C.3 On the contrary to this fallacy, an important fact is related to the possibility of the fecal-oral route of transmission which has been identified in multiple case studies and clinical settings. The nucleic acid of the virus has been detected in the feces and anal swabs of some COVID-19 patients, and live virions were shown to exist in fecal specimens in patients with negative oropharyngeal specimen, which indicates that viral infection of the gastrointestinal tract and the potential fecal-oral transmission can outlast the viral clearance in the respiratory tract.4 An observation that needs further investigation was actually reported from clinicians caring for infected patients, whereby expulsion of excess colonic gas which has an unpleasant odor with or without diarrhea has been noticed (unpublished data). Although this observation is not yet documented, it should be further analyzed and investigated. Whether abdominal gases in COVID-19 patients with gastrointestinal manifestations can be a potential mode of transmission of the virus needs to be ascertained. Other fallacies that relate to the size of the virus claimed that airborne spread is not possible due to the large size of the virus which makes it drop onto surfaces after 3 hours. It was also claimed that COVID-19 primarily spreads through the respiratory tract, by droplets, respiratory secretions, and direct contact and is not transmitted by aerosol, therefore, only infection control precautions and social distancing for at least 1 m would suffice to prevent the spread of the infection. However, the most recent studies reported that it could be transmitted as an airborne infection for distances exceeding 4 m.5 Within this context, there has been some confusion about the types of masks that should be used among healthcare teams caring for COVID-19 patients. Several developing countries have adopted the use of regular surgical masks among healthcare workers caring for COVID-19 patients early in the course of the disease. Medical health workers who primarily use this type of masks are susceptible to infection. Although this is not documented yet, but many healthcare workers in developing countries like Egypt and other countries like Italy and Saudi Arabia have been infected and unfortunately were deceased due to COVID-19. These types of masks alone without complete face shield are not adequate for protection against COVID-19.6 Within the context of cross-infection control, we would like to stress that donning and doffing of personal protective equipment (PPE) should be conducted in a particular order to prevent infection. The recommended sequence involves removal of the high level maximum protective masks as the last step in doffing of PPE. Handling the contaminated mask itself may transmit the virus and hence cause infection.7 A suggestion to prevent transmission while doffing involves that PPE undergoes disinfection in a special room or to utilize a specific equipment for disposal of used PPE before doffing. In conclusion, more facts about COVID-19 transmission and effective preventive measures should be revealed and disseminated among the medical community to preserve the precious lives of healthcare team members. The aim of this correspondence is to draw attention of healthcare workers caring for COVID-19 patients especially those working in developing countries to the possibility of transmission of infection through the gastrointestinal route with particular reference to colonic gases. We further warn them against the use of conventional surgical masks because it is useless in the clinical setting, and also warn them against handling of the contaminated masks during doffing of PPE. Here we suggest the use of disinfection of PPE before removal and the proper way of disposal.

Development of a highly effective low-cost vaporized hydrogen peroxide-based method for disinfection of personal protective equipment for their selective reuse during pandemics

BackgroundPersonal Protective Equipment (PPE) is required to safely work with biological agents of bacterial (i.e. Mycobacterium tuberculosis) or viral origin (Ebola and SARS). COVID-19 pandemic especially has created unforeseen public health challenges including a global shortage of PPE needed for the safety of health care workers (HCWs). Although sufficient stocks of PPE are currently available, their critical shortage may develop soon due to increase in demand and depletion of existing supply lines. To empower our HCWs and ensure their continued protection, proactive measures are urgently required to develop procedures to safely decontaminate the PPEs to allow their “selective reuse” during contingency situations.MethodsHerein, we have successfully developed a decontamination method based on vaporized hydrogen peroxide (VHP). We have used a range of concentration of hydrogen peroxide to disinfect PPE (coveralls, face-shields, and N-95 masks). To ensure a proper disinfection, we have evaluated three biological indicators namely Escherichia coli, Mycobacterium smegmatis and spores of Bacillus stearothermophilus, considered as the gold standard for disinfection processes. We next evaluated the impact of repeated VHP treatment on physical features, permeability, and fabric integrity of coveralls and N-95 masks. Next, we performed Scanning Electron Microscopy (SEM) to evaluate microscopic changes in fiber thickness of N-95 masks, melt blown layer or coverall body suits. Considering the fact that any disinfection procedure should be able to meet local requirements, our study included various regionally procured N-95 masks and coveralls available at our institute All India Institute of Medical Sciences (AIIMS), New Delhi, India. Lastly, the practical utility of VHP method developed herein was ascertained by operationalizing a dedicated research facility disinfecting used PPE during COVID-19.ResultsOur prototype studies show that a single VHP cycle (7–8% Hydrogen peroxide) could disinfect PPE and PPE housing room of about 1200 cubic feet (length10 ft × breadth 10 ft × height 12 ft) in less than 10 min, as noted by a complete loss of B. stearothermophilus spore revival. The results are consistent and reproducible as tested in over 10 cycles in our settings. Further, repeated VHP treatment did not result in any physical tear, deformity or other appreciable change in the coverall and N-95 masks. Our permeation tests evaluating droplet penetration did not reveal any change in permeability post-VHP treatments. Also, SEM analysis indeed revealed no significant change in fiber thickness or damage to fibers of coveralls or melt blown layer of N-95 masks essential for filtration. There was no change in user comfort and experience following VHP treatment of PPE. Based on results of these studies, and parameters developed and optimized, an institutional research facility to disinfect COVID-19 PPE is successfully established and operationalized with more than 80% recovery rate for used PPE post-disinfection.ConclusionsOur study, therefore, successfully establishes the utility of VHP to effectively disinfect PPE for a possible reuse as per the requirements. VHP treatment did not damage coveralls, cause physical deformity and also did not alter fabric architecture of melt blown layer. We observed that disinfection process was successful consistently and therefore believe that the VHP-based decontamination model will have a universal applicability and utility. This process can be easily and economically scaled up and can be instrumental in easing global PPE shortages in any biosafety facility or in health care settings during pandemic situation such as COVID-19.

Potential use of 3-(trimethoxysilyl)propyldimethyl octadecyl ammonium chloride as an antimicrobial and antiviral agent for the disinfection of personal protective equipment.

Currently, no vaccine or established therapeutic agents are available for coronavirus disease 2019. The sharp increase in demand for personal protective equipment (PPE) necessitates an improvement in the protective efficacy of PPE. We evaluated the potential antimicrobial and antiviral effects of a surface-coating disinfectant (3-(trimethoxysilyl)propyldimethyl octadecyl ammonium chloride, Si-QAC) when applied onto PPE. Si-QAC-pre-coated PPE was artificially contaminated with either influenza virus or Salmonella. The results showed significantly reduced influenza and Salmonella titers in Si-QAC-coated PPE; these antimicrobial effects lasted 7 days. This suggests that this surface-coating disinfectant effectively reduces pathogen contamination of PPE, enabling their safe and long-term use.

Preventing Viral Contamination: Effects of Wipe and Spray-based Decontamination of Gloves and Gowns.

We conducted a laboratory simulation to evaluate the contamination of environmental surfaces when using wipe vs spray methods of personal protective equipment (PPE) decontamination. We did not observe any environmental contamination with the bacteriophage MS-2 when bleach solution spray or wipes were used for PPE disinfection.

Disinfecting personal protective equipment with pulsed xenon ultraviolet as a risk mitigation strategy for health care workers

The doffing of personal protective equipment (PPE) after contamination with pathogens such as Ebola poses a risk to health care workers. Pulsed xenon ultraviolet (PX-UV) disinfection has been used to disinfect surfaces in hospital settings. This study examined the impact of PX-UV disinfection on an Ebola surrogate virus on glass carriers and PPE material to examine the potential benefits of using PX-UV to decontaminate PPE while worn, thereby reducing the pathogen load prior to doffing. Ultraviolet (UV) safety and coverage tests were also conducted. PX-UV exposure resulted in a significant reduction in viral load on glass carriers and PPE materials. Occupational Safety and Health Administration-defined UV exposure limits were not exceeded during PPE disinfection. Predoffing disinfection with PX-UV has potential as an additive measure to the doffing practice guidelines. The PX-UV disinfection should not be considered sterilization; all PPE should still be considered contaminated and doffed and disposed of according to established protocols.