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1.
PLoS One ; 15(8): e0237691, 2020.
Article in English | MEDLINE | ID: covidwho-717606

ABSTRACT

Efficient strategies to contain the coronavirus disease 2019 (COVID-19) pandemic are peremptory to relieve the negatively impacted public health and global economy, with the full scope yet to unfold. In the absence of highly effective drugs, vaccines, and abundant medical resources, many measures are used to manage the infection rate and avoid exhausting limited hospital resources. Wearing masks is among the non-pharmaceutical intervention (NPI) measures that could be effectively implemented at a minimum cost and without dramatically disrupting social practices. The mask-wearing guidelines vary significantly across countries. Regardless of the debates in the medical community and the global mask production shortage, more countries and regions are moving forward with recommendations or mandates to wear masks in public. Our study combines mathematical modeling and existing scientific evidence to evaluate the potential impact of the utilization of normal medical masks in public to combat the COVID-19 pandemic. We consider three key factors that contribute to the effectiveness of wearing a quality mask in reducing the transmission risk, including the mask aerosol reduction rate, mask population coverage, and mask availability. We first simulate the impact of these three factors on the virus reproduction number and infection attack rate in a general population. Using the intervened viral transmission route by wearing a mask, we further model the impact of mask-wearing on the epidemic curve with increasing mask awareness and availability. Our study indicates that wearing a face mask can be effectively combined with social distancing to flatten the epidemic curve. Wearing a mask presents a rational way to implement as an NPI to combat COVID-19. We recognize our study provides a projection based only on currently available data and estimates potential probabilities. As such, our model warrants further validation studies.


Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Disease Transmission, Infectious/prevention & control , Infection Control/methods , Masks/virology , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Coronavirus Infections/virology , Humans , Masks/supply & distribution , Models, Theoretical , Pneumonia, Viral/virology
2.
Epidemiol Infect ; 148: e154, 2020 07 14.
Article in English | MEDLINE | ID: covidwho-650362

ABSTRACT

There is limited information concerning the viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aerosols deposited on environmental surfaces and the effectiveness of infection prevention and control procedures on eliminating SARS-CoV-2 contamination in hospital settings. We examined the concentration of SARS-CoV-2 in aerosol samples and on environmental surfaces in a hospital designated for treating severe COVID-19 patients. Aerosol samples were collected by a microbial air sampler, and environmental surfaces were sampled using sterile premoistened swabs at multiple sites. Ninety surface swabs and 135 aerosol samples were collected. Only two swabs, sampled from the inside of a patient's mask, were positive for SARS-CoV-2 RNA. All other swabs and aerosol samples were negative for the virus. Our study indicated that strict implementation of infection prevention and control procedures was highly effective in eliminating aerosol and environmental borne SARS-CoV-2 RNA thereby reducing the risk of cross-infection in hospitals.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Cross Infection/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , RNA, Viral/isolation & purification , Viral Load , Aerosols , Betacoronavirus/genetics , Coronavirus Infections/transmission , Cross Infection/transmission , Cross Infection/virology , Environment , Environmental Microbiology , Hospitals, University , Humans , Masks/virology , Pneumonia, Viral/transmission
3.
J Hosp Infect ; 106(1): 10-19, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-635297

ABSTRACT

BACKGROUND: In the wake of the SARS-CoV-2 pandemic and unprecedented global demand, clinicians are struggling to source adequate access to personal protective equipment. Respirators can be in short supply, though are necessary to protect workers from SARS-CoV-2 exposure. Rapid decontamination and reuse of respirators may provide relief for the strained procurement situation. METHOD: In this study, we investigated the suitability of 70°C dry heat and microwave-generated steam (MGS) for reprocessing of FFP2/N95-type respirators, and Type-II surgical face masks. Staphylococcus aureus was used as a surrogate as it is less susceptible than enveloped viruses to chemical and physical processes. RESULTS: We observed >4 log10 reductions in the viability of dry S. aureus treated by dry heat for 90 min at 70°C and >6 log10 reductions by MGS for 90 s. After 3 reprocessing cycles, neither process was found to negatively impact the bacterial or NaCl filtration efficiency of the respirators that were tested. However, MGS was incompatible with Type-II surgical masks tested, as we confirmed that bacterial filtration capacity was completely lost following reprocessing. MGS was observed to be incompatible with some respirator types due to arcing observed around some types of metal nose clips and by loss of adhesion of clips to the mask. CONCLUSION: Considering the advantages and disadvantages of each approach, we propose a reprocessing personal protective equipment/face mask workflow for use in medical areas.


Subject(s)
Coronavirus Infections/prevention & control , Decontamination/methods , Equipment Reuse/standards , Hot Temperature , Masks/virology , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Respiratory Protective Devices/virology , Steam , Betacoronavirus , Guidelines as Topic , Humans , Microwaves
4.
PLoS One ; 15(7): e0234851, 2020.
Article in English | MEDLINE | ID: covidwho-627997

ABSTRACT

A lack of N95 Filtering Facepiece Respirators (FFRs) during the COVID-19 crisis has placed healthcare workers at risk. It is important for any N95 reuse strategy to determine the effects that proposed protocols would have on the physical functioning of the mask, as well as the practical aspects of implementation. Here we propose and implement a method of heating N95 respirators with moisture (85°C, 60-85% humidity). We test both mask filtration efficiency and fit to validate this process. Our tests focus on the 3M 1860, 3M 1870, and 3M 8210 Plus N95 models. After five cycles of the heating procedure, all three respirators pass both quantitative fit testing (score of >100) and show no degradation of mask filtration efficiency. We also test the Chen Heng V9501 KN95 and HKYQ N95 finding no degradation of mask filtration efficiency, however even for unheated masks these scored <50 for every fit test. The heating method presented here is scalable from individual masks to over a thousand a day with a single industrial convection oven, making this method practical for local application inside health-care facilities.


Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Decontamination/methods , Equipment Reuse , Heating/methods , Humidity , Masks/virology , Pneumonia, Viral/epidemiology , Respiratory Protective Devices/virology , Coronavirus Infections/virology , Filtration/instrumentation , Humans , Materials Testing/methods , Occupational Exposure/prevention & control , Pandemics , Pneumonia, Viral/virology
5.
ACS Nano ; 14(7): 9188-9200, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-614523

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 , Filtration , Humans , Masks/virology , Nanoparticles/chemistry , Nanoparticles/virology , Personal Protective Equipment/virology , Respiratory Protective Devices/virology , Textiles/adverse effects , Textiles/virology
6.
ACS Nano ; 14(7): 8846-8854, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-612577

ABSTRACT

The COVID-19 pandemic is endangering the world due to the spread of respiration droplets with viruses. Medical workers and frontline staff need to wear respirators to protect themselves from breathing in the virus-containing respiration droplets. The most frequently used state-of-the-art respirators are of N95 standard; however, they lack self-decontamination capabilities. In addition, the viruses and bacteria can accumulate on the respirator surfaces, possessing high risks to the wearers over long-term usage. Photothermal decontamination is a contactless, fast, low-cost, and widely available method, capable of decontaminating the respirators. Herein, we report a plasmonic photothermal and superhydrophobic coating on N95 respirators, possessing significantly better protection than existing personal protection equipment. The plasmonic heating can raise the surface temperature to over 80 °C for this type of respirator within 1 min of sunlight illumination. The superhydrophobic features prohibit respiration droplets from accumulating on the respirator surfaces. The presence of the silver nanoparticles can provide additional protection via the silver ion's disinfection toward microbes. These synergistic features of the composite coatings provide the N95 respirator with better protection and can inspire experts from interdisciplinary fields to develop better personal protection equipment to fight the COVID-19 pandemic.


Subject(s)
Disinfection/methods , Equipment Design/methods , Masks/standards , Personal Protective Equipment/standards , Printing, Three-Dimensional , Respiratory Protective Devices/standards , Coronavirus Infections/prevention & control , Equipment Design/instrumentation , Hot Temperature , Humans , Hydrophobic and Hydrophilic Interactions , Lasers , Masks/virology , Metal Nanoparticles/chemistry , Pandemics/prevention & control , Personal Protective Equipment/virology , Pneumonia, Viral/prevention & control , Resins, Synthetic/chemistry , Respiratory Protective Devices/virology , Silver/chemistry , Sunlight
7.
Am J Infect Control ; 48(8): 880-882, 2020 08.
Article in English | MEDLINE | ID: covidwho-472917

ABSTRACT

BACKGROUND: The need for protective masks greatly exceeds their global supply during the current COVID-19 pandemic. METHODS: We optimized the temperature used in the dry heat pasteurization method to destroy pathogens and decontaminate masks while retaining their filtering capacity. RESULTS: The current study showed that dry heat at both 60°C and 70°C for 1 hour could successfully kill 6 species of respiratory bacteria and one fungi species, and inactivate the H1N1 indicator virus. After being heated at 70°C for 1, 2, and 3 hours, the N95 respirators and surgical face masks showed no changes in their shape and components. The filtering efficiency of bacterial aerosol for N95 respirators were 98%, 98%, and 97% after being heated for 1, 2, and 3 hour, respectively, all of which were over the 95% efficiency required and similar to the value before being heated (99%). The filtering efficiency for surgical face masks was 97%, 97%, and 96% for 1, 2, and 3 hours of heating, respectively, all of which were also similar to the value before being heated (97%). CONCLUSIONS: This method can be used at home and can significantly resolve the current shortage of masks.


Subject(s)
Decontamination/methods , Masks/virology , Pasteurization/methods , Respiratory Protective Devices/virology , Betacoronavirus/pathogenicity , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Hot Temperature , Humans , Influenza A Virus, H1N1 Subtype/pathogenicity , Occupational Exposure/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , Ventilators, Mechanical/virology
8.
Am J Infect Control ; 48(8): 880-882, 2020 08.
Article in English | MEDLINE | ID: covidwho-437100

ABSTRACT

BACKGROUND: The need for protective masks greatly exceeds their global supply during the current COVID-19 pandemic. METHODS: We optimized the temperature used in the dry heat pasteurization method to destroy pathogens and decontaminate masks while retaining their filtering capacity. RESULTS: The current study showed that dry heat at both 60°C and 70°C for 1 hour could successfully kill 6 species of respiratory bacteria and one fungi species, and inactivate the H1N1 indicator virus. After being heated at 70°C for 1, 2, and 3 hours, the N95 respirators and surgical face masks showed no changes in their shape and components. The filtering efficiency of bacterial aerosol for N95 respirators were 98%, 98%, and 97% after being heated for 1, 2, and 3 hour, respectively, all of which were over the 95% efficiency required and similar to the value before being heated (99%). The filtering efficiency for surgical face masks was 97%, 97%, and 96% for 1, 2, and 3 hours of heating, respectively, all of which were also similar to the value before being heated (97%). CONCLUSIONS: This method can be used at home and can significantly resolve the current shortage of masks.


Subject(s)
Decontamination/methods , Masks/virology , Pasteurization/methods , Respiratory Protective Devices/virology , Betacoronavirus/pathogenicity , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Hot Temperature , Humans , Influenza A Virus, H1N1 Subtype/pathogenicity , Occupational Exposure/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , Ventilators, Mechanical/virology
9.
Am J Infect Control ; 48(8): 883-889, 2020 08.
Article in English | MEDLINE | ID: covidwho-361418

ABSTRACT

OBJECTIVE: The past 4 months, the emergence and spread of novel 2019 SARS-Cov-2 (COVID-19) has led to a global pandemic which is rapidly depleting supplies of personal protective equipment worldwide. There are currently over 1.6 million confirmed cases of COVID-19 worldwide which has resulted in more the 100,000 deaths. As these numbers grow daily, hospitals are being forced to reuse surgical masks in hopes of conserving their dwindling supply. Since COVID-19 will most likely have effects that last for many months, our nationwide shortage of masks poses a long term issue that must be addressed immediately. METHODS: Based on a previous study by Quan et al., a salt-based soaking strategy has been reported to enhance the filtration ability of surgical masks. We propose a similar soaking process which uses materials widely available in anyone's household. We tested this method of pretreating a variety of materials with a salt-based solution by a droplet test using fluorescently stained nanoparticles similar in size to the COVID-19 virus. RESULTS: In this study, we found that paper towels and surgical masks pretreated with the salt-based solution showed a noticeable increase in filtration of nanoparticles similar in size to the COVID-19 virus. We also show that the TWEEN20 used by Quan et al. is not a critical component for the solution, and using salt alone in solution still provides a dramatically increased level of protection. CONCLUSIONS: We believe this method will allow for healthcare workers to create a disposable added layer of protection to their surgical masks, N95s, or homemade masks by using household available products. Adoption of this method may play an essential role in ensuring the safety of healthcare workers during the COVID-19 pandemic and any pandemics that may arise in the future.


Subject(s)
Coronavirus Infections/prevention & control , Filtration/methods , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Masks/virology , Pandemics/prevention & control , Personal Protective Equipment/microbiology , Pneumonia, Viral/prevention & control , Betacoronavirus/pathogenicity , Health Personnel , Humans , Sodium Chloride/chemistry
11.
Exp Biol Med (Maywood) ; 245(11): 933-939, 2020 06.
Article in English | MEDLINE | ID: covidwho-245432

ABSTRACT

IMPACT STATEMENT: There is a critical shortage of personal protective equipment (PPE) around the globe. This article describes the safe collection, storage, and decontamination of N95 respirators using hydrogen peroxide vapor (HPV). This article is unique because it describes the HPV process in an operating room, and is therefore, a deployable method for many healthcare settings. Results presented here offer creative solutions to the current PPE shortage.


Subject(s)
Betacoronavirus/drug effects , Decontamination/methods , Hydrogen Peroxide/pharmacology , Masks/virology , Respiratory Protective Devices/virology , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control
12.
Nat Med ; 26(5): 676-680, 2020 05.
Article in English | MEDLINE | ID: covidwho-203367

ABSTRACT

We identified seasonal human coronaviruses, influenza viruses and rhinoviruses in exhaled breath and coughs of children and adults with acute respiratory illness. Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets. Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.


Subject(s)
Coronavirus Infections/transmission , Masks/virology , Pneumonia, Viral/transmission , Respiratory Tract Infections/transmission , Aerosols/isolation & purification , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Exhalation/physiology , Humans , Orthomyxoviridae/isolation & purification , Orthomyxoviridae/pathogenicity , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , RNA, Viral/isolation & purification , Respiratory Tract Infections/pathology , Respiratory Tract Infections/virology , Virus Shedding
13.
J Am Coll Surg ; 231(2): 275-280, 2020 Aug.
Article in English | MEDLINE | ID: covidwho-125470

ABSTRACT

Personal protective equipment (PPE) has been an invaluable yet limited resource when it comes to protecting healthcare workers against infection during the 2019 coronavirus (COVID-19) pandemic. In the US, N95 respirator supply chains are severely strained and conservation strategies are needed. A multidisciplinary team at the Washington University School of Medicine, Barnes Jewish Hospital, and BJC Healthcare was formed to implement a program to disinfect N95 respirators. The process described extends the life of N95 respirators using vaporized hydrogen peroxide (VHP) disinfection and allows healthcare workers to retain their own N95 respirator across a large metropolitan healthcare system.


Subject(s)
Coronavirus Infections/prevention & control , Disinfection/methods , Equipment Contamination/prevention & control , Hydrogen Peroxide/chemistry , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Masks/virology , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Academic Medical Centers , Betacoronavirus , Coronavirus Infections/epidemiology , Humans , Masks/supply & distribution , Missouri/epidemiology , Pneumonia, Viral/epidemiology
14.
ACS Nano ; 14(5): 6213-6221, 2020 05 26.
Article in English | MEDLINE | ID: covidwho-115548

ABSTRACT

The 2019 coronavirus outbreak (COVID-19) is affecting over 210 countries and territories, and it is spreading mainly by respiratory droplets. The use of disposable surgical masks is common for patients, doctors, and even the general public in highly risky areas. However, the current surgical masks cannot self-sterilize in order to reuse or be recycled for other applications. The resulting high economic and environmental costs are further damaging societies worldwide. Herein, we reported a unique method for functionalizing commercially available surgical masks with outstanding self-cleaning and photothermal properties. A dual-mode laser-induced forward transfer method was developed for depositing few-layer graphene onto low-melting temperature nonwoven masks. Superhydrophobic states were observed on the treated masks' surfaces, which can cause the incoming aqueous droplets to bounce off. Under sunlight illumination, the surface temperature of the functional mask can quickly increase to over 80 °C, making the masks reusable after sunlight sterilization. In addition, this graphene-coated mask can be recycled directly for use in solar-driven desalination with outstanding salt-rejection performance for long-term use. These roll-to-roll production-line-compatible masks can provide us with better protection against this severe virus. The environment can also benefit from the direct recycling of these masks, which can be used for desalinating seawater.


Subject(s)
Aerosols/chemistry , Graphite/chemistry , Masks/standards , Respiratory Protective Devices/standards , Absorption, Radiation , Disinfection/methods , Filtration , Hot Temperature , Hydrophobic and Hydrophilic Interactions , Light , Masks/virology , Respiratory Protective Devices/virology , Thermal Conductivity
15.
Eur Rev Med Pharmacol Sci ; 24(6): 3422-3425, 2020 03.
Article in English | MEDLINE | ID: covidwho-51504

ABSTRACT

The COVID-19 (Coronavirus disease 2019) spreads primarily through droplets of saliva or discharge from the nose. COVID-19 is predominantly considered as an unavoidable pandemic, and scientists are very curious about how to provide the best protection to the public before a vaccine can be made available. There is an urge to manufacture a greater number of masks to prevent any aerosol with microbes. Hence, we aim to develop an efficient viral inactivation system by exploiting active compounds from naturally occurring medicinal plants and infusing them into nanofiber-based respiratory masks. Our strategy is to develop fibrous filtration with three-layered masks using the compounds from medicinal plants for viral deactivation. These masks will be beneficial not just to healthcare workers but common citizens as well. In the absence of vaccination, productive masks can be worn to prevent transmission of airborne pathogenic aerosols and control diseases.


Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Masks/virology , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Humans
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