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1.
Infect Prev Pract ; 4(1): 100193, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1549845

ABSTRACT

Background: Physicians have had to perform numerous extubation procedures during the prolonged coronavirus disease 2019 (COVID 19) pandemic. Future pandemics caused by unknown pathogen may also present a risk of exposure to infectious droplets and aerosols. Aim: This study evaluated the ability of a newly developed aerosol barrier, "Extubation-Aerosol (EA)-Shield" to provide maximum protection from aerosol exposure during extubation via an aerosolised particle count and high-quality visualisation assessments. Methods: We employed a cough model having parameters similar to humans and used micron oil aerosol as well as titanium dioxide as aerosol tracers. Aerosol barrier techniques employing a face mask (group M) and EA-Shield (group H) were compared. Findings: The primary outcome was the difference in the number of particles contacting the physician's face before and after extubation. The maximum distances of aerosol dispersal after extubation were measured as the secondary outcomes. All aerosolised particles of the two tracers were significantly smaller in group H than in group M (p < 0.05). In addition, the sagittal and axial maximum distances and sagittal areas of aerosol dispersal for 3, 5, and 10 s after extubation were significantly smaller in group H than in group M (p < 0.05). Conclusion: This model indicates that EA-Shield could be highly effective in reducing aerosol exposure during extubation. Therefore, we recommend using it as an aerosol barrier when an infectious aerosol risk is suspected.

2.
Jpn J Infect Dis ; 74(5): 421-423, 2021 Sep 22.
Article in English | MEDLINE | ID: covidwho-1436359

ABSTRACT

Green tea extracts effectively inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro in a dose-dependent manner. Ten-fold serially diluted solutions of catechin mixture reagent from green tea were mixed with the viral culture fluid at a volume ratio of 9:1, respectively, and incubated at room temperature for 5 min. The solution of 10 mg/mL catechin reagent reduced the viral titer by 4.2 log and 1.0 mg/mL solution by one log. Pre-infection treatment of cells with the reagent alone did not affect viral growth. In addition, cells treated with only the reagent were assayed for host cell viability using the WST-8 system, and almost no host cell damage by the treatment was observed. These findings suggested that the direct treatment of virus with the reagent before inoculation decreased the viral activity and that catechins might have the potential to suppress SARSCoV-2 infection.


Subject(s)
Antiviral Agents/pharmacology , Catechin/pharmacology , SARS-CoV-2/drug effects , Tea/chemistry , Animals , COVID-19/virology , Cell Survival/drug effects , Chlorocebus aethiops , Dose-Response Relationship, Drug , Humans , Vero Cells , Viral Load/drug effects
3.
Sci Total Environ ; 773: 145525, 2021 Jun 15.
Article in English | MEDLINE | ID: covidwho-1062595

ABSTRACT

Airborne transmission is one of the routes for the spread of COVID-19 which is caused by inhalation of smaller droplets1 containing SARS-CoV-2 (i.e., either virus-laden particulate matter: PM and/or droplet nuclei) in an indoor environment. Notably, a significant fraction of the small droplets, along with respiratory droplets, is produced by both symptomatic and asymptomatic individuals during expiratory events such as breathing, sneezing, coughing and speaking. When these small droplets are exposed to the ambient environment, they may interact with PM and may remain suspended in the atmosphere even for several hours. Therefore, it is important to know the fate of these droplets and processes (e.g., physical and chemical) in the atmosphere to better understand airborne transmission. Therefore, we reviewed existing literature focussed on the transmission of SARS-CoV-2 in the spread of COVID-19 and present an environmental perspective on why airborne transmission hasn't been very conclusive so far. In addition, we discuss various environmental factors (e.g., temperature, humidity, etc.) and sampling difficulties, which affect the conclusions of the studies focussed on airborne transmission. One of the reasons for reduced emphasis on airborne transmission could be that the smaller droplets have less number of viruses as compared to larger droplets. Further, smaller droplets can evaporate faster, exposing SARS-CoV-2 within the small droplets to the environment, whose viability may further reduce. For example, these small droplets containing SARS-CoV-2 might also physically combine with or attach to pre-existing PM so that their behaviour and fate may be governed by PM composition. Thus, the measurement of their infectivity and viability is highly uncertain due to a lack of robust sampling system to separately collect virions in the atmosphere. We believe that the present review will help to minimize the gap in our understanding of the current pandemic and develop a robust epidemiological method for mortality assessment.


Subject(s)
COVID-19 , Cough , Exhalation , Humans , Humidity , SARS-CoV-2
4.
mSphere ; 5(5)2020 10 21.
Article in English | MEDLINE | ID: covidwho-889855

ABSTRACT

Guidelines from the CDC and the WHO recommend the wearing of face masks to prevent the spread of coronavirus (CoV) disease 2019 (COVID-19); however, the protective efficiency of such masks against airborne transmission of infectious severe acute respiratory syndrome CoV-2 (SARS-CoV-2) droplets/aerosols is unknown. Here, we developed an airborne transmission simulator of infectious SARS-CoV-2-containing droplets/aerosols produced by human respiration and coughs and assessed the transmissibility of the infectious droplets/aerosols and the ability of various types of face masks to block the transmission. We found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2 and that the protective efficiency was higher when masks were worn by a virus spreader. Importantly, medical masks (surgical masks and even N95 masks) were not able to completely block the transmission of virus droplets/aerosols even when completely sealed. Our data will help medical workers understand the proper use and performance of masks and determine whether they need additional equipment to protect themselves from infected patients.IMPORTANCE Airborne simulation experiments showed that cotton masks, surgical masks, and N95 masks provide some protection from the transmission of infective SARS-CoV-2 droplets/aerosols; however, medical masks (surgical masks and even N95 masks) could not completely block the transmission of virus droplets/aerosols even when sealed.


Subject(s)
Aerosols , Air Microbiology , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Masks/standards , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Betacoronavirus , COVID-19 , Health Personnel/education , Humans , Masks/classification , SARS-CoV-2
5.
J Thorac Dis ; 12(9): 4633-4642, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-819441

ABSTRACT

BACKGROUND: The pandemic of COVID-19 caused confusion in medical settings because of increased patient load, and caused many infections among medical staff which occurred through exposure to bio-particles discharged from patients. The risk of exposure became maximum at the examination of patients, particularly in the collection of respiratory specimens. Effective interventions to reduce the risk are needed. METHODS: A one-person booth consisting of curtain walls, frames, and fan-HEPA filter-unit (FFU) was designed. Using the airstream from/to FFU, it has dual functions as a positive/negative pressure machine to prevent pathogens in patient's cough to reach the medical staff inside/outside the booth, respectively. The curtain walls and positioning of the patient and staff were aerodynamically optimized for the best control of the airstream. RESULTS: The positive pressure booth is to isolate a staff inside to safely deal with a surge in the number of patients in situations like influenza pandemics. The negative pressure booth is to isolate a patient inside to protect a staff outside from dangerous contagious respiratory infectious diseases including COVID-19. A calculated airflow of the positive pressure machine efficiently pushed back bio-particles discharged from a person outside the booth. The bio-particles of a cough from a person inside the negative pressure booth was sucked into the FFU for filtration immediately after the discharge. The booth needed a short front curtain of a stair-cut shape, and a patient and a staff facing each other needed to be positioned at an angle 45° to the airstream for optimization of the airflow. CONCLUSIONS: The booth named Barriflow® would prevent the bioparticles of a patient's cough to reach the medical staff due to an aerodynamically designed airstream from the FFU and curtains surrounding it. It could be applied to cases of not only COVID-19 or influenza but also of other dangerous, contagious respiratory diseases.

6.
J Thorac Dis ; 12(7): 3682-3687, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-721975

ABSTRACT

BACKGROUND: The annual seasonal influenza epidemics in the winter season lead to many hospital admissions, increasing risks of nosocomial infections. Infectious diseases caused by contagious respiratory pathogens also pose a great risk to hospitals as has been seen in the current epidemic by a novel coronavirus infection. Such risk occurs in high density patient settings with few or no partitions, since the pathogens are transmitted by aerosols discharged from the patients. Possible interventions against the transmission are needed. METHODS: We developed a compact, lightweight, and portable hood designed to cover just the top half of a patient sitting or lying in bed, to limit the dissemination of infectious aerosols, constructed out of lightweight pipes, transparent plastic curtains, and a fan-filter-unit (FFU). The containment efficacy of the product was tested using an aerosolized cultured influenza virus tracer and an optimal airflow rate was determined according to the test results. It was tested for use in hospital wards during the 2016-2018 influenza seasons. RESULTS: The hood, named as Barrihood®, had dimensions height 172 cm, width 97 cm, length 38 cm, weighed 26 kg, and easily strolled and unfolded from its stored to its fully operational state of length 125 cm within a few minutes by a single operator. Optimal operational airflow-rate of the FFU was 420 L/min for containment of the aerosol particles. Eighty-one uninfected patients remained for 176 cumulative person-days within 1-4 m of influenza-infected patients isolated within the hood, without acquiring influenza infection. CONCLUSIONS: With the use of the hood, secondary influenza infection cases significantly decreased, compared to previous influenza seasons. It may be suited to hospitals with not enough/no negative pressure facilities, or without enough number of individual patient isolation rooms, and could contribute to decrease the risk of nosocomial infections.

7.
J Thorac Dis ; 12(7): 3500-3506, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-721679

ABSTRACT

BACKGROUND: We previously reported that we developed a compact and portable isolation hood that covers the top half of a patient sitting or lying in bed. The negative pressure inside the hood is generated by a fan-filter-unit (FFU) through which infectious aerosols from a patient are filtered. The outside area is kept clean which decreases the risk of nosocomial infections in hospital wards. We tried new applications of the hood. METHODS: The negative pressure hood was newly applied in an intensive care unit (ICU) as a place where a staff performs the practice of suctioning that generates much aerosol from the patient, as well as a waiting space for patients. Furthermore, the possibility that the hood can be converted to a positive pressure hood as a clean hood by switching the airflow direction of FFU was assessed. The cleaning efficacy of the inside of the hood was tested using an aerosolized cultured influenza virus tracer and an optimal airflow rate was determined according to the test results. RESULTS: The hood, named Barrihood, was found to be competent to be used (I) for tracheal suctioning in ICU, (II) as a waiting space for a child in a nursery who suddenly showed symptoms of the disease and waiting to be picked-up by the guardian, and (III) as a waiting space in a special outpatient clinic in a hospital for COVID-19 suspected cases to prevent dissemination of airborne pathogens. The positive pressure hood was also competent in keeping clean air quality that meets the standard class 100 of NASA's bio-clean room category. CONCLUSIONS: The proposed new applications will broaden the range of the hood's usage. The isolation hood could be useful in many settings to protect people outside the hood from a patient inside, or to protect an individual inside from air particles outside the hood, such as airborne pathogens, allergens, or hazardous particulate matter like PM2.5.

8.
Tohoku J Exp Med ; 251(1): 27-30, 2020 05.
Article in English | MEDLINE | ID: covidwho-326880

ABSTRACT

The number of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly increased, although the WHO declared a pandemic. However, drugs that function against SARS-CoV-2 have not been established. SARS-CoV-2 has been suggested to bind angiotensin-converting enzyme 2, the receptor of the SARS coronavirus. SARS coronavirus and coronavirus 229E, the cause of the common cold, replicate through cell-surface and endosomal pathways using a protease, the type II transmembrane protease. To examine the effects of protease inhibitors on the replication of coronavirus 229E, we pretreated primary cultures of human nasal epithelial (HNE) cells with camostat or nafamostat, each of which has been used for the treatment of pancreatitis and/or disseminated intravascular coagulation. HNE cells were then infected with coronavirus 229E, and viral titers in the airway surface liquid of the cells were examined. Pretreatment with camostat (0.1-10 µg/mL) or nafamostat (0.01-1 µg/mL) reduced the titers of coronavirus 229E. Furthermore, a significant amount of type II transmembrane protease protein was detected in the airway surface liquid of HNE cells. Additionally, interferons have been reported to have antiviral effects against SARS coronavirus. The additive effects of interferons on the inhibitory effects of other candidate drugs to treat SARS-CoV-2 infection, such as lopinavir, ritonavir and favipiravir, have also been studied. These findings suggest that protease inhibitors of this type may inhibit coronavirus 229E replication in human airway epithelial cells at clinical concentrations. Protease inhibitors, interferons or the combination of these drugs may become candidate drugs to inhibit the replication of SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus 229E, Human/drug effects , Coronavirus Infections/drug therapy , Gabexate/analogs & derivatives , Guanidines/pharmacology , Pneumonia, Viral/drug therapy , Protease Inhibitors/pharmacology , Virus Replication/drug effects , Benzamidines , Betacoronavirus/drug effects , COVID-19 , Cells, Cultured , Coronavirus 229E, Human/enzymology , Coronavirus 229E, Human/physiology , Culture Media, Conditioned , Epithelial Cells/virology , Esters , Gabexate/pharmacology , Humans , Nasal Mucosa/cytology , Pandemics , Primary Cell Culture , SARS-CoV-2 , Serine Endopeptidases/physiology , Spike Glycoprotein, Coronavirus/metabolism , Viral Load
9.
Respir Investig ; 58(3): 155-168, 2020 May.
Article in English | MEDLINE | ID: covidwho-154704

ABSTRACT

BACKGROUND: Coronavirus 229E (HCoV-229E), one of the causes of the common cold, exacerbates chronic obstructive pulmonary disease (COPD) and bronchial asthma. Long-acting muscarinic antagonists and ß2-agonists and inhaled corticosteroids inhibit the exacerbation of COPD and bronchial asthma caused by infection with viruses, including HCoV-229E. However, the effects of these drugs on HCoV-229E replication and infection-induced inflammation in the human airway are unknown. METHODS: Primary human nasal (HNE) and tracheal (HTE) epithelial cell cultures were infected with HCoV-229E. RESULTS: Pretreatment of HNE and HTE cells with glycopyrronium or formoterol decreased viral RNA levels and/or titers, the expression of the HCoV-229E receptor CD13, the number and fluorescence intensity of acidic endosomes where HCoV-229E RNA enters the cytoplasm, and the infection-induced production of cytokines, including IL-6, IL-8, and IFN-ß. Treatment of the cells with the CD13 inhibitor 2'2'-dipyridyl decreased viral titers. Pretreatment of the cells with a combination of three drugs (glycopyrronium, formoterol, and budesonide) exerted additive inhibitory effects on viral titers and cytokine production. Pretreatment of HNE cells with glycopyrronium or formoterol reduced the susceptibility to infection, and pretreatment with the three drugs inhibited activation of nuclear factor-kappa B p50 and p65 proteins. Pretreatment with formoterol increased cAMP levels and treatment with cAMP decreased viral titers, CD13 expression, and the fluorescence intensity of acidic endosomes. CONCLUSIONS: These findings suggest that glycopyrronium, formoterol, and a combination of glycopyrronium, formoterol, and budesonide inhibit HCoV-229E replication partly by inhibiting receptor expression and/or endosomal function and that these drugs modulate infection-induced inflammation in the airway.


Subject(s)
Adrenergic beta-2 Receptor Agonists/pharmacology , Budesonide/pharmacology , Coronavirus/physiology , Cytokines/metabolism , Epithelial Cells/metabolism , Epithelial Cells/virology , Formoterol Fumarate/pharmacology , Glycopyrrolate/pharmacology , Muscarinic Antagonists/pharmacology , Nasal Mucosa/cytology , Trachea/cytology , Virus Replication/drug effects , CD13 Antigens/metabolism , Cells, Cultured , Humans
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