Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 423
Filter
Add filters

Year range
3.
Int J Environ Res Public Health ; 18(4)2021 02 08.
Article in English | MEDLINE | ID: covidwho-1079658

ABSTRACT

BACKGROUND: During the SARS-CoV-2 pandemic, there was shortage of the standard respiratory protective equipment (RPE). The aim of this study was to develop a procedure to test the performance of alternative RPEs used in the care of COVID-19 patients. METHODS: A laboratory-based test was developed to compare RPEs by total inward leakage (TIL). We used a crossflow nebulizer to produce a jet spray of 1-100 µm water droplets with a fluorescent marker. The RPEs were placed on a dummy head and sprayed at distances of 30 and 60 cm. The outcome was determined as the recovery of the fluorescent marker on a membrane filter placed on the mouth of the dummy head. RESULTS: At 30 cm, a type IIR surgical mask gave a 17.7% lower TIL compared with an FFP2 respirator. At 60 cm, this difference was similar, with a 21.7% lower TIL for the surgical mask compared to the respirator. When adding a face shield, the TIL at 30 cm was further reduced by 9.5% for the respirator and 16.6% in the case of the surgical mask. CONCLUSIONS: A safe, fast and very sensitive test method was developed to assess the effectiveness of RPE by comparison under controlled conditions.


Subject(s)
/prevention & control , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Masks/standards , Personal Protective Equipment/standards , Respiratory Protective Devices/standards , Aerosols/adverse effects , Humans , Occupational Exposure/prevention & control , Ventilators, Mechanical , Water
4.
PLoS One ; 16(1): e0245019, 2021.
Article in English | MEDLINE | ID: covidwho-1079325

ABSTRACT

The knowledge on the deposition and retention of the viral particle of SARS-CoV-2 in the respiratory tract during the very initial intake from the ambient air is of prime importance to understand the infectious process and COVID-19 initial symptoms. We propose to use a modified version of a widely tested lung deposition model developed by the ICRP, in the context of the ICRP Publication 66, that provides deposition patterns of microparticles in different lung compartments. In the model, we mimicked the "environmental decay" of the virus, determined by controlled experiments related to normal speeches, by the radionuclide 11C that presents comparable decay rates. Our results confirm clinical observations on the high virus retentions observed in the extrathoracic region and the lesser fraction on the alveolar section (in the order of 5), which may shed light on physiopathology of clinical events as well on the minimal inoculum required to establish infection.


Subject(s)
/virology , /physiology , Aerosols/analysis , Carbon Radioisotopes , Humans , Lung/metabolism , Lung/pathology , Lung/virology , Models, Biological , Respiratory System/metabolism , Respiratory System/virology
5.
Cir Cir ; 89(1): 4-11, 2021.
Article in English | MEDLINE | ID: covidwho-1077009

ABSTRACT

Background: The coronavirus disease 2019 (COVID-19) outbreak have major implications in conventional surgical practice. As the number of patients with this diagnosis is rising, the infection risk for the surgical staff will be higher. Few publications have addressed the surgical management of patients diagnosed with COVID-19. Objective: To assess recommendations for care of patients and surgical team during the COVID-19 pandemic. Method: MEDLINE, Embase and the Cochrane Database of Systematic Reviews (April 2020) were searched the key words "COVID-19", "PROTOCOL" and "SURGERY". Relevant recommendations, guidelines and cases series were checked for the most accurate information for apply to our center. Results: We found 379 papers that included the key words. A total of 25 papers were included in the manuscript based in the pertinence of the recommendations. Three major topics were selected: perioperative, intraoperative and postoperative. Conclusion: As an attempt to regulate the surgical team approach, we present recommendations to preserve patients and surgical staff safety with high quality standards of care through reproducible strategies applicable in most hospital centers.


Subject(s)
/prevention & control , Cross Infection/prevention & control , Infection Control/methods , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Infectious Disease Transmission, Professional-to-Patient/prevention & control , Pandemics , Aerosols , Air Pollution, Indoor , Appointments and Schedules , Disinfection/methods , Equipment Contamination/prevention & control , Humans , Mexico , Occupational Exposure , Operating Rooms , Patient Isolation , Perioperative Care , Personal Protective Equipment , Personnel, Hospital , Recovery Room , Sterilization/methods , Surgical Equipment
6.
PLoS One ; 16(2): e0246819, 2021.
Article in English | MEDLINE | ID: covidwho-1076271

ABSTRACT

Since the outbreak of the COVID-19 pandemic, singing activities for children and young people have been strictly regulated with far-reaching consequences for music education in schools and ensemble and choir singing in some places. This is also due to the fact, that there has been no reliable data available on aerosol emissions from adolescents speaking, singing, and shouting. By utilizing a laser particle counter in cleanroom conditions we show, that adolescents emit fewer aerosol particles during singing than what has been known so far for adults. In our data, the emission rates ranged from 16 P/s to 267 P/s for speaking, 141 P/s to 1240 P/s for singing, and 683 P/s to 4332 P/s for shouting. The data advocate an adaptation of existing risk management strategies and rules of conduct for groups of singing adolescents, like gatherings in an educational context, e.g. singing lessons or choir rehearsals.


Subject(s)
Aerosols/analysis , Singing , Speech , Adolescent , Disease Outbreaks , Environmental Monitoring/instrumentation , Female , Humans , Male
7.
Proc Natl Acad Sci U S A ; 118(8)2021 02 23.
Article in English | MEDLINE | ID: covidwho-1075324

ABSTRACT

COVID-19 transmits by droplets generated from surfaces of airway mucus during processes of respiration within hosts infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. We studied respiratory droplet generation and exhalation in human and nonhuman primate subjects with and without COVID-19 infection to explore whether SARS-CoV-2 infection, and other changes in physiological state, translate into observable evolution of numbers and sizes of exhaled respiratory droplets in healthy and diseased subjects. In our observational cohort study of the exhaled breath particles of 194 healthy human subjects, and in our experimental infection study of eight nonhuman primates infected, by aerosol, with SARS-CoV-2, we found that exhaled aerosol particles vary between subjects by three orders of magnitude, with exhaled respiratory droplet number increasing with degree of COVID-19 infection and elevated BMI-years. We observed that 18% of human subjects (35) accounted for 80% of the exhaled bioaerosol of the group (194), reflecting a superspreader distribution of bioaerosol analogous to a classical 20:80 superspreader of infection distribution. These findings suggest that quantitative assessment and control of exhaled aerosol may be critical to slowing the airborne spread of COVID-19 in the absence of an effective and widely disseminated vaccine.


Subject(s)
/physiopathology , Exhalation/physiology , Obesity/physiopathology , Aerosols , Age Factors , Animals , Body Mass Index , /virology , Cohort Studies , Humans , Mucus/chemistry , Mucus/virology , Obesity/epidemiology , Obesity/virology , Particle Size , Primates , Respiratory System/metabolism , Viral Load
8.
Epidemiol Prev ; 44(5-6 Suppl 2): 334-339, 2020.
Article in Italian | MEDLINE | ID: covidwho-1068155

ABSTRACT

Aim of this paper is to describe the management of an outbreak of COVID-19 in a slaughtering and meat processing plant in Bari Province (Southern Italy). At the end of the outbreak investigation, 18.4% of the employees were positive to the molecular test for SARS-CoV-2. Higher prevalence has been reported in the bovine slaughtering house and swine meat processing plant.In addition to lack of physical distancing and correct use of personal protective equipment, the spread of the virus has been eased by low level of literacy, indoor microclimate, intensive working time, and aerosol-generating procedures in specific areas of the processing plant where more positive cases have been detected. The analysis of this cluster may suggest specific actions to prevent similar outbreaks in the future.


Subject(s)
Abattoirs/organization & administration , Disease Outbreaks , Food Handling , Food Industry/organization & administration , Infection Control/organization & administration , Meat , Occupational Diseases/epidemiology , Pandemics , /isolation & purification , Abattoirs/statistics & numerical data , Adult , Aerosols , Air Pollution, Indoor , Animals , Asymptomatic Infections/epidemiology , Cattle , Contact Tracing , Databases, Factual , Educational Status , Equipment Contamination , Female , Food Handling/instrumentation , Food Handling/methods , Food Handling/statistics & numerical data , Humans , Italy/epidemiology , Male , Middle Aged , Personal Protective Equipment , Sheep , Swine
9.
Epidemiol Prev ; 44(5-6 Suppl 2): 152-159, 2020.
Article in English | MEDLINE | ID: covidwho-1068135

ABSTRACT

The determinants of the risk of becoming infected by SARS-CoV-2, contracting COVID-19, and being affected by the more serious forms of the disease have been generally explored in merely qualitative terms. It seems reasonable to argue that the risk patterns for COVID-19 have to be usefully studied in quantitative terms too, whenever possible applying the same approach to the relationship 'dose of the exposure vs pathological response' commonly used for chemicals and already followed for several biological agents to SARS-CoV-2, too. Such an approach is of particular relevance in the fields of both occupational epidemiology and occupational medicine, where the identification of the sources of a dangerous exposure and of the web of causation of a disease is often questionable and questioned: it is relevant when evaluating the population risk, too. Specific occupational scenarios, basically involving health workers, exhibit important proportions of both subjects simply infected by SARS-CoV-2 and of ill subjects with, respectively, mild, moderate, and severe disease. Similar patterns have been described referring to various circumstances of community exposure, e.g., standing in crowded public places, travelling on crowded means of transport, living in accommodation or care homes, living in the same household as a COVID-19 case. The hypothesis that these findings are a consequence not only of high probabilities of exposure, but also of high doses (as a product of both intensity and duration, with possible autonomous effects of peaks of exposure) deserves to be systematically tested, in order to reconstruct the web of causation of COVID-19 individual and clustered cases and to cope with situations at critical risk for SARS-CoV-2, needing to be identified, mapped, and dealt with at the right time. A limited but consistent set of papers supporting these assumptions has been traced in the literature. Under these premises, the creation of a structured inventory of both values of viral concentrations in the air (in case and if possible, of surface contaminations too) and of viral loads in biological matrixes is proposed, with the subsequent construction of a scenario-exposure matrix. A scenario-exposure matrix for SARS-CoV-2 may represent a useful tool for research and practical risk management purposes, helping to understand the possibly critical circumstances for which no direct exposure measure is available (this is an especially frequent case, in contexts of low socio-economic level) and providing guidance to determine evidence-based public health strategies.


Subject(s)
/virology , Environmental Exposure , Viral Load , Viremia/virology , Aerosols , Air Microbiology , Air Pollution, Indoor , /epidemiology , Cross Infection/epidemiology , Cross Infection/transmission , Cross Infection/virology , Crowding , Disease Transmission, Infectious , Environmental Monitoring , Family Characteristics , Fomites/virology , Humans , Infectious Disease Transmission, Patient-to-Professional , Institutionalization , Occupational Exposure , Risk , Risk Assessment , Time Factors , Transportation
10.
PLoS One ; 16(2): e0244127, 2021.
Article in English | MEDLINE | ID: covidwho-1067399

ABSTRACT

INTRODUCTION: Olfactory dysfunction (OD) affects a majority of COVID-19 patients, is atypical in duration and recovery, and is associated with focal opacification and inflammation of the olfactory epithelium. Given recent increased emphasis on airborne transmission of SARS-CoV-2, the purpose of the present study was to experimentally characterize aerosol dispersion within olfactory epithelium (OE) and respiratory epithelium (RE) in human subjects, to determine if small (sub 5µm) airborne aerosols selectively deposit in the OE. METHODS: Healthy adult volunteers inhaled fluorescein-labeled nebulized 0.5-5µm airborne aerosol or atomized larger aerosolized droplets (30-100µm). Particulate deposition in the OE and RE was assessed by blue-light filter modified rigid endoscopic evaluation with subsequent image randomization, processing and quantification by a blinded reviewer. RESULTS: 0.5-5µm airborne aerosol deposition, as assessed by fluorescence gray value, was significantly higher in the OE than the RE bilaterally, with minimal to no deposition observed in the RE (maximum fluorescence: OE 19.5(IQR 22.5), RE 1(IQR 3.2), p<0.001; average fluorescence: OE 2.3(IQR 4.5), RE 0.1(IQR 0.2), p<0.01). Conversely, larger 30-100µm aerosolized droplet deposition was significantly greater in the RE than the OE (maximum fluorescence: OE 13(IQR 14.3), RE 38(IQR 45.5), p<0.01; average fluorescence: OE 1.9(IQR 2.1), RE 5.9(IQR 5.9), p<0.01). CONCLUSIONS: Our data experimentally confirm that despite bypassing the majority of the upper airway, small-sized (0.5-5µm) airborne aerosols differentially deposit in significant concentrations within the olfactory epithelium. This provides a compelling aerodynamic mechanism to explain atypical OD in COVID-19.


Subject(s)
Aerosols/analysis , /complications , Olfactory Mucosa/physiopathology , Adult , Aerosols/administration & dosage , /virology , /virology , Host-Pathogen Interactions , Humans , Olfactory Mucosa/virology , Smell
11.
BMC Oral Health ; 21(1): 52, 2021 02 05.
Article in English | MEDLINE | ID: covidwho-1067221

ABSTRACT

BACKGROUND: Transmission of COVID-19 via salivary aerosol particles generated when using handpieces or ultrasonic scalers is a major concern during the COVID-19 pandemic. The aim of this study was to assess the spread of dental aerosols on patients and dental providers during aerosol-generating dental procedures. METHODS: This pilot study was conducted with one volunteer. A dental unit used at the dental school for general dental care was the site of the experiment. Before the study, three measurement meters (DustTrak 8534, PTrak 8525 and AeroTrak 9306) were used to measure the ambient distribution of particles in the ambient air surrounding the dental chair. The volunteer wore a bouffant, goggles, and shoe covers and was seated in the dental chair in supine position, and covered with a surgical drape. The dentist and dental assistant donned bouffant, goggles, face shields, N95 masks, surgical gowns and shoe covers. The simulation was conducted by using a high-speed handpiece with a diamond bur operating in the oral cavity for 6 min without touching the teeth. A new set of measurement was obtained while using an ultrasonic scaler to clean all teeth of the volunteer. For both aerosol generating procedures, the aerosol particles were measured with the use of saliva ejector (SE) and high-speed suction (HSS) followed a separate set of measurement with the additional use of an extra oral high-volume suction (HVS) unit that was placed close to the mouth to capture the aerosol in addition to SE and HSS. The distribution of the air particles, including the size and concentration of aerosols, was measured around the patient, dentist, dental assistant, 3 feet above the patient, and the floor. RESULTS: Four locations were identified with elevated aerosol levels compared to the baseline, including the chest of the dentist, the chest of patient, the chest of assistant and 3 feet above the patient. The use of additional extra oral high volume suction reduced aerosol to or below the baseline level. CONCLUSIONS: The increase of the level of aerosol with size less than 10 µm was minimal during dental procedures when using SE and HSS. Use of HVS further reduced aerosol levels below the ambient levels.


Subject(s)
Pandemics , Aerosols , Humans , Pilot Projects , Saliva , Schools, Dental
12.
Otolaryngol Head Neck Surg ; 164(2): 305-307, 2021 02.
Article in English | MEDLINE | ID: covidwho-1067044

ABSTRACT

Current COVID-19 vaccine candidates are administered by injection and designed to produce an IgG response, preventing viremia and the COVID-19 syndrome. However, systemic respiratory vaccines generally provide limited protection against viral replication and shedding within the airway, as this requires a local mucosal secretory IgA response. Indeed, preclinical studies of adenovirus and mRNA candidate vaccines demonstrated persistent virus in nasal swabs despite preventing COVID-19. This suggests that systemically vaccinated patients, while asymptomatic, may still be become infected and transmit live virus from the upper airway. COVID-19 is known to spread through respiratory droplets and aerosols. Furthermore, significant evidence has shown that many clinic and surgical endonasal procedures are aerosol generating. Until further knowledge is acquired regarding mucosal immunity following systemic vaccination, otolaryngology providers should maintain precautions against viral transmission to protect the proportion of persistently vulnerable patients who exhibit subtotal vaccine efficacy or waning immunity or who defer vaccination.


Subject(s)
/prevention & control , Nasal Mucosa/virology , Aerosols , Asymptomatic Infections , Humans
13.
Proc Natl Acad Sci U S A ; 118(8)2021 02 23.
Article in English | MEDLINE | ID: covidwho-1066038

ABSTRACT

Several lines of existing evidence support the possibility of airborne transmission of coronavirus disease 2019 (COVID-19). However, quantitative information on the relative importance of transmission pathways of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains limited. To evaluate the relative importance of multiple transmission routes for SARS-CoV-2, we developed a modeling framework and leveraged detailed information available from the Diamond Princess cruise ship outbreak that occurred in early 2020. We modeled 21,600 scenarios to generate a matrix of solutions across a full range of assumptions for eight unknown or uncertain epidemic and mechanistic transmission factors. A total of 132 model iterations met acceptability criteria (R 2 > 0.95 for modeled vs. reported cumulative daily cases and R 2 > 0 for daily cases). Analyzing only these successful model iterations quantifies the likely contributions of each defined mode of transmission. Mean estimates of the contributions of short-range, long-range, and fomite transmission modes to infected cases across the entire simulation period were 35%, 35%, and 30%, respectively. Mean estimates of the contributions of larger respiratory droplets and smaller respiratory aerosols were 41% and 59%, respectively. Our results demonstrate that aerosol inhalation was likely the dominant contributor to COVID-19 transmission among the passengers, even considering a conservative assumption of high ventilation rates and no air recirculation conditions for the cruise ship. Moreover, close-range and long-range transmission likely contributed similarly to disease progression aboard the ship, with fomite transmission playing a smaller role. The passenger quarantine also affected the importance of each mode, demonstrating the impacts of the interventions.


Subject(s)
Aerosols , Disease Outbreaks/statistics & numerical data , Models, Theoretical , Quarantine/standards , Ships/statistics & numerical data , /diagnosis , /virology , Humans , Quarantine/methods , Quarantine/statistics & numerical data
14.
Sci Rep ; 11(1): 3179, 2021 02 04.
Article in English | MEDLINE | ID: covidwho-1065959

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected millions and killed more than 1.7 million people worldwide as of December 2020. Healthcare providers are at increased risk of infection when caring for patients with COVID-19. The mechanism of transmission of SARS-CoV-2 is beginning to emerge as airborne spread in addition to direct droplet and indirect contact as main routes of transmission. Here, we report on the design, construction, and testing of the BADGER (Box for Aerosol and Droplet Guarding and Evacuation in Respiratory Infection), an affordable, scalable device that contains droplets and aerosol particles, thus minimizing the risk of infection to healthcare providers. A semi-sealed environment is created inside the BADGER, which is placed over the head of the patient and maintains at least 12-air changes per hour using in-wall vacuum suction. Multiple hand-ports enable healthcare providers to perform essential tasks on a patient's airway and head. Overall, the BADGER has the potential to contain large droplets and small airborne particles as demonstrated by simulated qualitative and quantitative assessments to provide an additional layer of protection for healthcare providers treating COVID-19 and future respiratory contagions.


Subject(s)
Infectious Disease Transmission, Patient-to-Professional/prevention & control , Protective Devices , Aerosols , /transmission , Humans
15.
Epidemiol Infect ; 149: e24, 2021 01 14.
Article in English | MEDLINE | ID: covidwho-1065752

ABSTRACT

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is highly contagious, and the coronavirus disease 2019 (COVID-19) pandemic caused by it has forced many countries to adopt 'lockdown' measures to prevent the spread of the epidemic through social isolation of citizens. Some countries proposed universal mask wearing as a protection measure of public health to strengthen national prevention efforts and to limit the wider spread of the epidemic. In order to reveal the epidemic prevention efficacy of masks, this paper systematically evaluates the experimental studies of various masks and filter materials, summarises the general characteristics of the filtration efficiency of isolation masks with particle size, and reveals the actual efficacy of masks by combining the volume distribution characteristics of human exhaled droplets with different particle sizes and the SARS-CoV-2 virus load of nasopharynx and throat swabs from patients. The existing measured data show that the filtration efficiency of all kinds of masks for large particles and extra-large droplets is close to 100%. From the perspective of filtering the total number of pathogens discharged in the environment and protecting vulnerable individuals from breathing live viruses, the mask has a higher protective effect. If considering the weighted average filtration efficiency with different particle sizes, the filtration efficiencies of the N95 mask and the ordinary mask are 99.4% and 98.5%, respectively. The mask can avoid releasing active viruses to the environment from the source of infection, thus maximising the protection of vulnerable individuals by reducing the probability of inhaling a virus. Therefore, if the whole society strictly implements the policy of publicly wearing masks, the risk of large-scale spread of the epidemic can be greatly reduced. Compared with the overall cost of social isolation, limited personal freedoms and forced suspension of economic activities, the inconvenience for citizens caused by wearing masks is perfectly acceptable.


Subject(s)
/epidemiology , Masks/standards , Aerosols , Humans , Nasopharynx/virology , Oropharynx/virology , Particle Size , Viral Load
16.
Br J Community Nurs ; 26(2): 76-80, 2021 Feb 02.
Article in English | MEDLINE | ID: covidwho-1063515

ABSTRACT

COVID-19 has changed the landscape of healthcare in the UK since the first confirmed case in January 2020. Most of the resources have been directed towards reducing transmission in the hospital and clinical environment, but little is known about what community nurses can do to reduce the risk when they nurse people in their own homes? This article looks at what COVID-19 is, how it is spread and how health professionals are at an increased risk from aerosol-generating procedures (AGPs). There is also a discussion on the benefit of mask usage. It defines what AGPs are, which clinical procedures are AGPs, including ones performed in the community setting, and which identified clinical practices that have been mistaken for AGPs. There is also a discussion on the suitability of performing cardiopulmonary resuscitation (CPR). It also describes how to reduce the risk by the use of full personal protective equipment (PPE) and other strategies when AGPs are performed in a patient's home. It ends with general advice about managing the risk of COVID-19 transmission with patients in their homes.


Subject(s)
/prevention & control , Communicable Disease Control , Home Care Services , Personal Protective Equipment , /pathogenicity , Aerosols , Disease Transmission, Infectious/prevention & control , Humans , United Kingdom
17.
PLoS One ; 16(2): e0246543, 2021.
Article in English | MEDLINE | ID: covidwho-1063221

ABSTRACT

Dental turbines and scalers, used every day in dental operatories, feature built-in water spray that generates considerable amounts of water aerosol. The problem is that it is not exactly known how much. Since the outbreak of COVID-19, several aerosol safety recommendations have been issued-based on little empirical evidence, as almost no data are available on the exact aerosol concentrations generated during dental treatment. Similarly, little is known about the differences in the efficacy of different commercially available aerosol control systems to reduce in-treatment aerosol load. In this in vitro study, we used spectrometry to explore these questions. The time-dependent effect of conventional airing on aerosol concentrations was also studied. Everyday patient treatment situations were modeled. The test setups were defined by the applied instrument and its spray direction (high-speed turbine with direct/indirect airspray or ultrasonic scaler with indirect airspray) and the applied aerosol control system (the conventional high-volume evacuator or a lately introduced aerosol exhaustor). Two parameters were analyzed: total number concentration in the entire measurement range of the spectrometer and total number concentration within the 60 to 384 nm range. The results suggest that instrument type and spray direction significantly influence the resulting aerosol concentrations. Aerosol generation by the ultrasonic scaler is easily controlled. As for the high-speed turbine, the efficiency of control might depend on how exactly the instrument is used during a treatment. The results suggest that scenarios where the airspray is frequently directed toward the air of the operatory are the most difficult to control. The tested control systems did not differ in their efficiency, but the study could not provide conclusive results in this respect. With conventional airing through windows with a standard fan, a safety airing period of at least 15 minutes between treatments is recommended.


Subject(s)
Aerosols/adverse effects , Dental Instruments/virology , Dentistry/methods , Aerosols/administration & dosage , Aerosols/analysis , Equipment Design , Humans , Particle Size , /isolation & purification
18.
Int J Environ Res Public Health ; 18(4)2021 02 03.
Article in English | MEDLINE | ID: covidwho-1060788

ABSTRACT

We discuss the implications of possible contagion of COVID-19 through e-cigarette aerosol (ECA) for prevention and mitigation strategies during the current pandemic. This is a relevant issue when millions of vapers (and smokers) must remain under indoor confinement and/or share public outdoor spaces with non-users. The fact that the respiratory flow associated with vaping is visible (as opposed to other respiratory activities) clearly delineates a safety distance of 1-2 m along the exhaled jet to prevent direct exposure. Vaping is a relatively infrequent and intermittent respiratory activity for which we infer a mean emission rate of 79.82 droplets per puff (6-200, standard deviation 74.66) comparable to mouth breathing, it adds into shared indoor spaces (home and restaurant scenarios) a 1% extra risk of indirect COVID-19 contagion with respect to a "control case" of existing unavoidable risk from continuous breathing. As a comparative reference, this added relative risk increases to 44-176% for speaking 6-24 min per hour and 260% for coughing every 2 min. Mechanical ventilation decreases absolute emission levels but keeps the same relative risks. As long as direct exposure to the visible exhaled jet is avoided, wearing of face masks effectively protects bystanders and keeps risk estimates very low. As a consequence, protection from possible COVID-19 contagion through vaping emissions does not require extra interventions besides the standard recommendations to the general population: keeping a social separation distance of 2 m and wearing of face masks.


Subject(s)
Aerosols , Electronic Nicotine Delivery Systems , Humans , Public Policy
19.
Phys Rev Lett ; 126(3): 034502, 2021 Jan 22.
Article in English | MEDLINE | ID: covidwho-1060608

ABSTRACT

To quantify the fate of respiratory droplets under different ambient relative humidities, direct numerical simulations of a typical respiratory event are performed. We found that, because small droplets (with initial diameter of 10 µm) are swept by turbulent eddies in the expelled humid puff, their lifetime gets extended by a factor of more than 30 times as compared to what is suggested by the classical picture by Wells, for 50% relative humidity. With increasing ambient relative humidity the extension of the lifetimes of the small droplets further increases and goes up to around 150 times for 90% relative humidity, implying more than 2 m advection range of the respiratory droplets within 1 sec. Employing Lagrangian statistics, we demonstrate that the turbulent humid respiratory puff engulfs the small droplets, leading to many orders of magnitude increase in their lifetimes, implying that they can be transported much further during the respiratory events than the large ones. Our findings provide the starting points for larger parameter studies and may be instructive for developing strategies on optimizing ventilation and indoor humidity control. Such strategies are key in mitigating the COVID-19 pandemic in the present autumn and upcoming winter.


Subject(s)
Body Fluids/chemistry , Body Fluids/virology , Models, Biological , Aerosols/chemistry , Air Microbiology , Air Movements , Computer Simulation , Disease Transmission, Infectious , Exhalation , Humans , Pandemics , /isolation & purification
20.
J Otolaryngol Head Neck Surg ; 50(1): 3, 2021 Jan 18.
Article in English | MEDLINE | ID: covidwho-1059689

ABSTRACT

BACKGROUND: Tracheostomy, as an aerosol-generating procedure, is considered as a high-risk surgery for health care workers (HCWs) during the coronavirus disease (COVID-19) pandemic. Current recommendations are to perform tracheostomy after a period of intubation of > 14 days, with two consecutive negative throat swab tests, to lower the risk of contamination to HCWs. However, specific data for this recommendation are lacking. Therefore, this study aimed to evaluate viral shedding into the environment, including HCWs, associated with bedside tracheostomy in the intensive care unit. METHODS: Samples obtained from the medical environment immediately after tracheostomy, including those from 19 surfaces, two air samples at 10 and 50 cm from the surgical site, and from the personal protective equipment (PPE) of the surgeon and assistant, were tested for the presence of severe acute respiratory syndrome coronavirus 2 in eight cases of bedside tracheostomy. We evaluated the rate of positive tests from the different samples obtained. RESULTS: Positive samples were identified in only one of the eight cases. These were obtained for the air sample at 10 cm and from the bed handrail and urine bag. There were no positive test results from the PPE samples. The patient with positive samples had undergone early tracheostomy, at 9 days after intubation, due to a comorbidity. CONCLUSIONS: Our preliminary results indicate that delayed tracheostomy, after an extended period of endotracheal intubation, might be a considerably less contagious procedure than early tracheostomy (defined as < 14 days after intubation).


Subject(s)
Air Microbiology , Equipment Contamination , Intensive Care Units , Tracheostomy , Virus Shedding , Aerosols , Aged , Female , Humans , Intubation, Intratracheal , Male , Middle Aged
SELECTION OF CITATIONS
SEARCH DETAIL