Aerial transmission of SARS-CoV-2 virus (and pathogens in general) through environmental e-cigarette aerosol

AbstractWe examine the plausibility, scope and risks of aerial transmission of pathogens (including the SARS-CoV-2 virus) through respiratory droplets carried by exhaled e–cigarette aerosol (ECA). Observational and laboratory data suggests considering cigarette smoking and mouth breathing through a mouthpiece as convenient proxies to infer the respiratory mechanics and droplets sizes and their rate of emission that should result from vaping. To infer distances for possible direct contagion we model exhaled ECA flow as an intermittent turbulent jet evolving into an unstable puff, estimating for low intensity vaping (practiced by 80-90% of vapers) ECA expirations the emission of 2-230 respiratory submicron droplets per puff a horizontal distance spread of 1-2 meters, with intense vaping possibly carrying hundreds and up to 1000 droplets per puff in the submicron range a distance spread over 2 meters. Bystanders exposed to low intensity expirations from an infectious vaper in indoor spaces (home and restaurant scenarios) face a 1% increase of risk of indirect contagion with respect to a “control case” scenario defined by exclusively rest breathing without vaping. This relative added risk becomes 5 – 17% for high intensity vaping, 40 – 90% and over 260% for speaking or coughing (without vaping). This risk evaluation remains practically unchanged in shared spaces with universal usage of face masks. We estimate that disinfectant properties of glycols in ECA are unlikely to act efficiently on pathogens carried by vaping expirations under realistic conditions.

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Modeling Aerial Transmission of Pathogens (Including the SARS-CoV-2 Virus) through Aerosol Emissions from E-Cigarettes

Applied Sciences ◽

10.3390/app11146355 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6355

Author(s):

Roberto A. Sussman ◽

Eliana Golberstein ◽

Riccardo Polosa

Keyword(s):

Cigarette Smoking ◽

Theoretical Modeling ◽

Horizontal Distance ◽

Axially Symmetric ◽

Low Intensity ◽

Direct Exposure ◽

Submicron Droplets ◽

Starting Jet ◽

Aerosol Emissions ◽

Respiratory Droplets

We examine the plausibility of aerial transmission of pathogens (including the SARS-CoV-2 virus) through respiratory droplets that might be carried by exhaled e-cigarette aerosol (ECA). Given the lack of empiric evidence on this phenomenon, we consider available evidence on cigarette smoking and respiratory droplet emission from mouth breathing through a mouthpiece as convenient proxies to infer the capacity of vaping to transport pathogens in respiratory droplets. Since both exhaled droplets and ECA droplets are within the Stokes regime, the ECA flow acts effectively as a visual tracer of the expiratory flow. To infer quantitatively the direct exposure distance, we consider a model that approximates exhaled ECA flow as an axially symmetric intermittent steady starting jet evolving into an unstable puff, an evolution that we corroborate by comparison with photographs and videos of actual vapers. On the grounds of all this theoretical modeling, we estimate for low-intensity vaping (practiced by 80–90% of vapers) the emission of 6–210 (median 39.9, median deviation 67.3) respiratory submicron droplets per puff and a horizontal distance spread of 1–2 m, with intense vaping possibly emitting up to 1000 droplets per puff in the submicron range with a distance spread over 2 m. The optical visibility of the ECA flow has important safety implications, as bystanders become instinctively aware of the scope and distance of possible direct contagion through the vaping jet.

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Analytic modeling and risk assessment of aerial transmission of SARS-CoV-2 virus through vaping expirations in shared micro-environments

10.21203/rs.3.rs-340115/v1 ◽

2021 ◽

Author(s):

Roberto Sussman ◽

Eliana Golberstein ◽

Riccardo Polosa

Keyword(s):

Mechanical Ventilation ◽

Risk Model ◽

Case Scenario ◽

Direct Exposure ◽

Containment Measures ◽

Nicotine Consumption ◽

Contagion Risk ◽

Droplet Nuclei ◽

Respiratory Droplets ◽

Indoor Spaces

Abstract Background. E-cigarettes are an important harm reduction tool that provides smokers an alternative for nicotine consumption that is much safer than smoking. It is important to asses its safety under preventive and containment measures undertaken during the COVID-19 pandemic. Methods. We develop a theoretical risk model to assess the contagion risk by aerial transmission of the SARS-CoV-2 virus carried by e–cigarette aerosol (ECA) in shared indoor spaces, a home and restaurant scenarios, with natural and mechanical ventilation, with and without face masks. We also provide the theoretical elements to explain the visibility of exhaled ECA, which has important safety implications. Results. In a home or restaurant scenarios bystanders exposed to ECA expirations by an infectious vaper (and not wearing face masks) face a 1% increase of risk of contagion with respect to a “control case” scenario defined by exclusively rest breathing without vaping. This relative added risk becomes 5 - 17% for high intensity vaping, 44 - 176% and over 260% for speaking for various periods or coughing (all without vaping). Mechanical ventilation significantly decrease infective emissions but keep the same proportionality in risk percentages. Face masks of common usage effectively protect wearers from respiratory droplets and droplet nuclei possibly emitted by mask-less vapers as long as they avoid direct exposure to the visible exhaled vaping jet. Conclusions. Vaping emissions in shared indoor spaces involve only a minuscule added risk of COVID-19 contagion with respect to the already existing (unavoidable) risk from continuous breathing, significantly less than speaking or coughing. Protection of bystanders from this contagion does not require extra preventive measures besides those already recommended (1.5 meters separation and wearing face masks).

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Analytic modeling and risk assessment of aerial transmission of SARS-CoV-2 virus through vaping expirations in shared micro-environments

10.31219/osf.io/8vxag ◽

2021 ◽

Author(s):

Roberto A Sussman ◽

Eliana Golberstein ◽

Riccardo Polosa

Keyword(s):

Mechanical Ventilation ◽

Risk Model ◽

Case Scenario ◽

Direct Exposure ◽

Containment Measures ◽

Nicotine Consumption ◽

Contagion Risk ◽

Droplet Nuclei ◽

Respiratory Droplets ◽

Indoor Spaces

Background. E-cigarettes are an important harm reduction tool that provides smokers an alternative for nicotine consumption that is much safer than smoking. It is important to asses its safety under preventive and containment measures undertaken during the COVID-19 pandemic.Methods. We develop a theoretical risk model to assess the contagion risk by aerial trans mission of the SARS-CoV-2 virus carried by e–cigarette aerosol (ECA) in shared indoor spaces, a home and restaurant scenarios, with natural and mechanical ventilation, with and without face masks. We also provide the theoretical elements to explain the visibility of exhaled ECA, which has important safety implications.Results. In a home or restaurant scenarios bystanders exposed to ECA expirations by an infectious vaper (and not wearing face masks) face a 1% increase of risk of contagion with respect to a “control case” scenario defined by exclusively rest breathing without vaping. This relative added risk becomes 5 - 17% for high intensity vaping, 44 - 176% and over 260% for speaking for various periods or coughing (all without vaping). Mechanical ventilation significantly decrease infective emissions but keep the same proportionality in risk percentages. Face masks of common usage effectively protect wearers from respiratory droplets and droplet nuclei possibly emitted by mask-less vapers as long as they avoid direct exposure to the visible exhaled vaping jet.Conclusions. Vaping emissions in shared indoor spaces involve only a minuscule added risk of COVID-19 contagion with respect to the already existing (unavoidable) risk from continuous breathing, significantly less than speaking or coughing. Protection of bystanders from this contagion does not require extra preventive measures besides those already recommended (1.5 meters separation and wearing face masks).

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Coupling Computational Fluid Dynamics Simulations and Statistical Moments for Designing Healthy Indoor Spaces

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16050800 ◽

2019 ◽

Vol 16 (5) ◽

pp. 800 ◽

Cited By ~ 1

Author(s):

Shamia Hoque ◽

Firoza Omar

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Air Flow ◽

Particle Dispersion ◽

Statistical Moments ◽

Dispersion Pattern ◽

Case Scenario ◽

Worst Case ◽

Site Specific ◽

Indoor Spaces

Cross-contamination between occupants in an indoor space may occur due to transfer of infectious aerosols. Computational fluid dynamics (CFD) provides detailed insight into particle transport in indoor spaces. However, such simulations are site-specific. This study couples CFD with statistical moments and establishes a framework that transitions site-specific results to generating guidelines for designing “healthy” indoor spaces. Eighteen cases were simulated, and three parameters were assessed: inlet/outlet location, air changes per hour, and the presence/absence of desks. Aerosol release due to a simulated “sneeze” in a two-dimensional ventilated space was applied as a test case. Mean, standard deviation, and skewness of the velocity profiles and particle locations gave an overall picture of the spread and movement of the air flow in the domain. A parameter or configuration did not dominate the values, confirming the significance of considering the combined influence of multiple parameters for determining localized air-flow characteristics. Particle clustering occurred more when the inlet was positioned above the outlet. The particle dispersion pattern could be classified into two time zones: “near time”, <60 s, and “far time”, >120 s. Based on dosage, the 18 cases were classified into three groups ranging from worst case scenario to best case scenario.

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Prospective Population-Based Analysis of Characteristics and Therapy Options in AML: The Case of Catalonia (PERIS Project)

Blood ◽

10.1182/blood-2020-139160 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 32-33

Author(s):

Montserrat Hoyos ◽

Ana Garrido ◽

Montserrat Arnan ◽

Marina Diaz-Beyá ◽

Olga Salamero ◽

...

Keyword(s):

Clinical Trials ◽

Board Of Directors ◽

Hematopoietic Cell Transplantation ◽

Clinical Laboratory ◽

Laboratory Data ◽

Population Based ◽

Advanced Age ◽

Age Group ◽

Advisory Committees ◽

Low Intensity

Introduction:Acute myeloid leukemia (AML) real-world incidence has been investigated in a limited number of European countries such as Sweden, Denmark and a few others. These prospective population-based analyses give a more precise idea of AML as a health problem than registry data from cooperative groups or other sources, that usually include selected cases as part of research studies and/or therapy trials. In October 2016, the Autonomous Government of Catalonia funded a project (PERIS SLT002/16/00433) to prospectively collect all AML cases from our territory. Objective:To investigate the incidence, characteristics and treatment decisions in all consecutive AML patients diagnosed in Catalonia between January 2017 and December 2019. Methods:Inclusion criteria were diagnosis of AML according the WHO 2016 criteria, both primary and secondary (APL excluded) with an age >18 years. The project was disseminated to all hospitals from Catalonia regardless of their size, having at least one hematologist. A specific informatics tool was implemented for remote reporting of the cases. All data were anonymized. In parallel, a circuit for centralized bio banking of patients' samples was designed. The database included the main clinical, laboratory data as well as the initial therapeutic approach. Cases included in our CETLAM group cooperative studies were automatically linked to the trial database for collecting detailed information. Statistical analyses were performed with R packages. Results:Assuming an incidence of AML of 4 cases per 100,000 inhabitants (based on previous reported data from others), we expected 912 cases during three years in the 7,6 million population of Catalonia. Our prospective registry included 750 consecutive AML patients, 82% of the expected cases. The remaining 18% could be explained by the exclusion of APL, age below 18 years, or underreporting. Seventy percent of patients (n=527) were diagnosed and treated in the 5 large University Hospitals from Barcelona and the two adjacent cities (Badalona and Hospitalet). Table 1 shows the main characteristics of the patients. Among the 390 patients up to 70 years, 272 (70%) were enrolled in the CETLAM AML-12 protocol that included intensive chemotherapy (ICT) and risk adapted hematopoietic cell transplantation (HCT). Forty-one additional patients (11%) in this age group received other ICT in different clinical trials. A remaining 73 patients (20%) were treated with other intensive or non-intensive approaches outside trials. In the group of 360 patients older than 70 years only a 33% (n= 119) were treated under the risk-adapted CETLAM AML-16 protocol for elderly AML patients. This trial included ICT as in the CETLAM-12 in case of favorable genetic features; this was received by 13 of the 119 patients (11%) enrolled. The remaining patients of CETLAM-16 were treated with low-intensity chemotherapy (oral fludarabine, subcutaneous (SC) cytarabine and G-CSF or azacytidine) and 97 additional elderly patients were included in other clinical trials mostly with targeted and hypomethylating agents (27%). Other active therapies outside trials (usually low-intensity) were administered in 50 additional patients (14%) whereas the remaining 94 patients (26%) only received supportive measures (transfusions, hydroxyurea, antibiotics, palliation, or no treatment), because of one or more of the following: advanced age, poor AML features or severe clinical condition. Overall survival (OS) of the whole series at 2 years was 31±2% (CI: 27-35). Patients younger than 70 years had a 2-year OS of 47±3% (CI: 41-53) compared to 11±3% (CI: 7-17) for those above 70 years (p<0.001) (Image 1). Conclusions:This prospective study is highly representative of the diagnosis and treatment of AML in Catalonia. The median age at diagnosis was 70 years. Of note, 81% of patients up to 70 years were enrolled in ICT trials. The proportion of patients in trials in the elderly group was lower although still remarkable (60%). In this advanced age group, a 26% of patients were treated with supportive measures only. Despite the high inclusion rate in clinical trials, only one third of newly diagnosed AML patients have the probability to survive at 2 years, with a dismal outcome in those above 70 years. Therefore, the investigation of novel and more effective treatments remains mandatory. This series will be detailed and updated during the meeting. Disclosures Salamero: Pfizer:Consultancy;Jazz Pharmaceuticals:Consultancy, Honoraria;Daichii Sankyo:Honoraria;Novartis:Consultancy, Honoraria;Celgene:Consultancy, Honoraria.Olivera:BAYER:Consultancy;Pfizer:Consultancy, Speakers Bureau;Daiichi Sankyo:Consultancy, Speakers Bureau;Boehringer Ingelheim:Consultancy, Speakers Bureau.Sureda Balari:Celgene:Consultancy, Honoraria;Merck Sharpe and Dohme:Consultancy, Honoraria, Speakers Bureau;Sanofi:Consultancy, Honoraria;Novartis:Consultancy, Honoraria;Gilead/Kite:Consultancy, Honoraria;Janssen:Consultancy, Honoraria;Incyte:Consultancy;Roche:Honoraria;BMS:Speakers Bureau;Celgene/Bristol-Myers Squibb:Consultancy, Honoraria;Takeda:Consultancy, Honoraria, Speakers Bureau.Ribera:Pfizer, Amgen:Research Funding;Pfizer, Amgen, Ariad, Novartis:Consultancy, Speakers Bureau.Sierra:Jazz Pharmaceuticals:Research Funding;Pfizer:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Daiichi Sankyo:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Abbvie:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Novartis:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Astellas:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Roche:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Gilead-Kite:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Issues of operational integrity in membrane drinking water plants

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0152 ◽

2003 ◽

Vol 3 (5-6) ◽

pp. 73-80 ◽

Cited By ~ 4

Author(s):

W. Johnson ◽

T. MacCormick

Keyword(s):

Drinking Water ◽

Laboratory Data ◽

Full Scale ◽

Human Pathogens ◽

Membrane Systems ◽

Case Scenario ◽

Fiber Failure ◽

Worst Case ◽

Virus Removal ◽

Water Plants

In the last five years over 100 microfiltration (MF) and ultrafiltration (UF) drinking water plants have been installed in Europe with a combined output of some 1,500 ML/day. The impetus behind this growth is concern over drinking water quality, regulatory pressure, the rapidly declining costs of membrane systems, and consumer pressures for non-chemical treatment. Although the principal justification for membrane plants is their capacity to remove human pathogens more effectively than conventional treatment, the ability of large plants to retain an integral barrier is not well understood. Currently available technology can monitor a full-scale membrane plant for integrity against passage of bacteria and parasites but not viruses. In essence the plant operator has to rely on the membrane manufacturer – on an assumption that if the membrane is not compromised at a level of 1 to 2 μm (the current practical level of measurement) it is also not compromised for virus removal. This paper quantifies the loss of integrity that can occur from membrane fiber failure. It explains the mathematical models used to describe bypass flow through compromised fibers and correlates the results with laboratory tests. Both are compared with artificially compromised fibers in a large full-scale operating plant. Under the worst case scenario where a fiber breaks close to the pot (collection end of the filtration module or element) the relative loss of integrity between alternative process designs from a single broken fiber can differ by as much as 2 log reduction values. The analysis demonstrates the need for monitoring methodology that that can track incremental changes in integrity to allow scheduled rather than emergency maintenance. It highlights the need for regulatory authorities to approve membrane systems based on actual operating performance in preference to laboratory data.

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Usefulness of Respiratory Mechanics and Laboratory Parameter Trends as Markers of Early Treatment Success in Mechanically Ventilated Severe Coronavirus Disease: A Single-Center Pilot Study

Journal of Clinical Medicine ◽

10.3390/jcm10112513 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2513

Author(s):

Daisuke Kasugai ◽

Masayuki Ozaki ◽

Kazuki Nishida ◽

Hiroaki Hiraiwa ◽

Naruhiro Jingushi ◽

...

Keyword(s):

Time Course ◽

Respiratory Mechanics ◽

Treatment Success ◽

Laboratory Data ◽

Single Center ◽

Mixed Effect ◽

Mechanically Ventilated ◽

Physiological Dead Space ◽

Reactive Protein ◽

Using Data

Whether a patient with severe coronavirus disease (COVID-19) will be successfully liberated from mechanical ventilation (MV) early is important in the COVID-19 pandemic. This study aimed to characterize the time course of parameters and outcomes of severe COVID-19 in relation to the timing of liberation from MV. This retrospective, single-center, observational study was performed using data from mechanically ventilated COVID-19 patients admitted to the ICU between 1 March 2020 and 15 December 2020. Early liberation from ventilation (EL group) was defined as successful extubation within 10 days of MV. The trends of respiratory mechanics and laboratory data were visualized and compared between the EL and prolonged MV (PMV) groups using smoothing spline and linear mixed effect models. Of 52 admitted patients, 31 mechanically ventilated COVID-19 patients were included (EL group, 20 (69%); PMV group, 11 (31%)). The patients’ median age was 71 years. While in-hospital mortality was low (6%), activities of daily living (ADL) at the time of hospital discharge were significantly impaired in the PMV group compared to the EL group (mean Barthel index (range): 30 (7.5–95) versus 2.5 (0–22.5), p = 0.048). The trends in respiratory compliance were different between patients in the EL and PMV groups. An increasing trend in the ventilatory ratio during MV until approximately 2 weeks was observed in both groups. The interaction between daily change and earlier liberation was significant in the trajectory of the thrombin–antithrombin complex, antithrombin 3, fibrinogen, C-reactive protein, lymphocyte, and positive end-expiratory pressure (PEEP) values. The indicator of physiological dead space increases during MV. The trajectory of markers of the hypercoagulation status, inflammation, and PEEP were significantly different depending on the timing of liberation from MV. These findings may provide insight into the pathophysiology of COVID-19 during treatment in the critical care setting.

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Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking

10.1101/2021.09.16.21263702 ◽

2021 ◽

Author(s):

Jayme P. Coyle ◽

Raymond C Derk ◽

William G Lindsley ◽

Theresa Boots ◽

Francoise M. Blachere ◽

...

Keyword(s):

Indoor Environment ◽

Respiratory Activity ◽

Aerosol Particles ◽

Inhalation Exposure ◽

Mitigation Strategies ◽

Engineering Controls ◽

Particle Exposure ◽

Adequate Ventilation ◽

Respiratory Droplets ◽

Indoor Spaces

To limit community spread of SARS-CoV-2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3-ply cotton masks reduced exposure to 0.3-3 μm coughed and exhaled aerosol particles by > 77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, i.e., coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a combination of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment.

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ENERGY ANALYSIS OF A NONLINEAR MODEL OF THE NORMAL HUMAN LUNG

Journal of Biological System ◽

10.1142/s0218339000000080 ◽

2000 ◽

Vol 08 (02) ◽

pp. 115-139 ◽

Cited By ~ 28

Author(s):

A. ATHANASIADES ◽

F. GHORBEL ◽

J. W. CLARK ◽

S. C. NIRANJAN ◽

J. OLANSEN ◽

...

Keyword(s):

Nonlinear Model ◽

Respiratory Mechanics ◽

Work Of Breathing ◽

Laboratory Data ◽

Upper Airways ◽

Peripheral Airways ◽

Viscoelastic Element ◽

Wall Compliance ◽

The Individual ◽

Natural Breathing

Despite the existence of respiratory mechanics models in the literature, rarely one finds analytical expressions that predict the work of breathing (WOB) associated with natural breathing maneuvers in non-ventilated subjects. In the present study, we develop relations that explicitly identify WOB, based on a proposed nonlinear model of respiratory mechanics. The model partitions airways resistance into three components (upper, middle and small), includes a collapsible airways segment, a viscoelastic element describing lung tissue dynamics and a static chest wall compliance. The individual contribution of these respiratory components on WOB is identified and analyzed. For instance, according to model predictions, during the forced vital capacity (FVC) maneuver, most of the work is expended against dissipative forces, mainly during expiration. In addition, expiratory dissipative work during FVC is almost equally partitioned among the upper airways and the collapsible airways resistances. The former expends work at the beginning of expiration, the latter at the end of expiration. The contribution of the peripheral airways is small. Our predictions are validated against laboratory data collected from volunteer subjects and using the esophageal catheter balloon technique.

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Delayed Aseptic Swelling After Fixation of Talar Neck Fracture with a Biodegradable Poly-L-Lactide Rod: Case Reports

Foot & Ankle International ◽

10.1177/107110079801900913 ◽

1998 ◽

Vol 19 (9) ◽

pp. 634-637 ◽

Cited By ~ 22

Author(s):

Nobuyuki Yoshino ◽

Shinro Takai ◽

Yoshinobu Watanabe ◽

Keiji Kamata ◽

Yasusuke Hirasawa

Keyword(s):

Magnetic Resonance Imaging ◽

Surgical Treatment ◽

Magnetic Resonance ◽

Case Reports ◽

Laboratory Data ◽

Resonance Imaging ◽

Low Intensity ◽

Biodegradable Poly ◽

Neck Fracture ◽

Weighted Magnetic Resonance Imaging

A 63-year-old woman complained of acute swelling and pain in her ankle at 15 months, after fixation of a talar neck fracture with poly-L-lactide rods. Roentgenographic and laboratory data revealed no abnormalities, but T1-weighted magnetic resonance imaging showed a diffuse area of low intensity in the talus. After nonweightbearing for 1 month, local findings had disappeared and the area of low intensity shown by magnetic resonance imaging had decreased without surgical treatment. Although there have been some reports of aseptic swelling or synovitis after fixation of a fracture with polyglycolide rods or screws, there has been no report of such cases with poly-L-lactide rods or screws.

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