scholarly journals Towards Improved Social Distancing Guidelines: Space and Time Dependence of Virus Transmission from Speech-driven Aerosol Transport Between Two Individuals

2020 ◽  
Author(s):  
Fan Yang ◽  
Amir A. Pahlavan ◽  
Simon Mendez ◽  
Manouk Abkarian ◽  
Howard A. Stone
Keyword(s):  
Time Dependence ◽  
Contact Time ◽  
Air Flow ◽  
Infected Individual ◽  
Virus Transmission ◽  
Susceptible Individual ◽  
Aerosol Transport ◽  
Social Distancing ◽  
Space And Time

It is now recognized that aerosol transport contributes to the transmission of the SARS-CoV-2 virus. Here we improve existing social distancing guidelines for airborne pathogens, which are typically given in terms of distance with vague statements (if any) about contact times. Also, estimates of inhalation of virus in a contaminated space usually assume a well-mixed environment, which is realistic for some, but not all, situations. In particular, we consider a local casual interaction of an infected individual and a susceptible individual, both maskless, account for the air flow and aerosol transport characteristics of speaking and breathing, and propose social distancing guidelines that involve both space and contact time, based on a conservative model of the interactions.

scholarly journals Breathing, virus transmission, and social distancing—An experimental visualization study

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045205
Author(s):  
Venugopal Arumuru ◽  
Jangyadatta Pasa ◽  
Sidhartha Sankar Samantaray ◽  
Vaibhavsingh Surendrasingh Varma
Keyword(s):  
Virus Transmission ◽  
Social Distancing

scholarly journals Effectiveness of Face Masks in Reducing the Spread of COVID-19: A Model-Based Analysis

2021 ◽  
pp. 0272989X2110190
Author(s):  
Isabelle J. Rao ◽  
Jacqueline J. Vallon ◽  
Margaret L. Brandeau
Keyword(s):  
New York ◽  
Infected Individual ◽  
Disease Model ◽  
World Health ◽  
Sensitivity Analyses ◽  
Reproductive Number ◽  
Social Distancing ◽  
Health Organization ◽  
Almost All ◽  
Mask Effectiveness

Background The World Health Organization and US Centers for Disease Control and Prevention recommend that both infected and susceptible people wear face masks to protect against COVID-19. Methods We develop a dynamic disease model to assess the effectiveness of face masks in reducing the spread of COVID-19, during an initial outbreak and a later resurgence, as a function of mask effectiveness, coverage, intervention timing, and time horizon. We instantiate the model for the COVID-19 outbreak in New York, with sensitivity analyses on key natural history parameters. Results During the initial epidemic outbreak, with no social distancing, only 100% coverage of masks with high effectiveness can reduce the effective reproductive number [Formula: see text] below 1. During a resurgence, with lowered transmission rates due to social distancing measures, masks with medium effectiveness at 80% coverage can reduce [Formula: see text] below 1 but cannot do so if individuals relax social distancing efforts. Full mask coverage could significantly improve outcomes during a resurgence: with social distancing, masks with at least medium effectiveness could reduce [Formula: see text] below 1 and avert almost all infections, even with intervention fatigue. For coverage levels below 100%, prioritizing masks that reduce the risk of an infected individual from spreading the infection rather than the risk of a susceptible individual from getting infected yields the greatest benefit. Limitations Data regarding COVID-19 transmission are uncertain, and empirical evidence on mask effectiveness is limited. Our analyses assume homogeneous mixing, providing an upper bound on mask effectiveness. Conclusions Even moderately effective face masks can play a role in reducing the spread of COVID-19, particularly with full coverage, but should be combined with social distancing measures to reduce [Formula: see text] below 1. [Box: see text]

scholarly journals Examining the interplay between face mask usage, asymptomatic transmission, and social distancing on the spread of COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam Catching ◽  
Sara Capponi ◽  
Ming Te Yeh ◽  
Simone Bianco ◽  
Raul Andino
Keyword(s):  
Social Distance ◽  
Large Fraction ◽  
Real Life ◽  
Virus Transmission ◽  
Face Mask ◽  
Social Distancing ◽  
Viral Spread ◽  
The Face ◽  
Asymptomatic Individuals ◽  
High Virus

AbstractCOVID-19’s high virus transmission rates have caused a pandemic that is exacerbated by the high rates of asymptomatic and presymptomatic infections. These factors suggest that face masks and social distance could be paramount in containing the pandemic. We examined the efficacy of each measure and the combination of both measures using an agent-based model within a closed space that approximated real-life interactions. By explicitly considering different fractions of asymptomatic individuals, as well as a realistic hypothesis of face masks protection during inhaling and exhaling, our simulations demonstrate that a synergistic use of face masks and social distancing is the most effective intervention to curb the infection spread. To control the pandemic, our models suggest that high adherence to social distance is necessary to curb the spread of the disease, and that wearing face masks provides optimal protection even if only a small portion of the population comply with social distance. Finally, the face mask effectiveness in curbing the viral spread is not reduced if a large fraction of population is asymptomatic. Our findings have important implications for policies that dictate the reopening of social gatherings.

scholarly journals A roadmap: Social distancing physical activity data collection to protect those with intellectual disabilities

2021 ◽  
pp. 174462952110096
Author(s):  
Whitley J Stone ◽  
Kayla M Baker
Keyword(s):  
Physical Activity ◽  
Data Collection ◽  
Intellectual Disabilities ◽  
Research Methods ◽  
Virus Transmission ◽  
Future Research ◽  
Activity Data ◽  
Physical Activity Data ◽  
Social Distancing ◽  
Novel Coronavirus

The novel coronavirus may impact exercise habits of those with intellectual disabilities. Due to the mandated discontinuation of face-to-face research, investigators must adapt projects to protect all involved while collecting objective physical activity metrics. This brief report outlines a modification process of research methods to adhere to social distancing mandates present during COVID-19. Actions taken included electronic consent and assent forms, an electronic survey, and mailing an accelerometer with included instructions. The amended research methods were implemented without risk for virus transmission or undue burden on the research team, participant, or caregiver. Recruitment was likely impacted by the coronavirus-mediated quarantine, plausibly resulting in bias. Objective physical activity data collection can be sufficiently modified to protect those with intellectual disabilities and investigators. Future research designs may require greater participant incentives and the creation of in-home participation.

scholarly journals Simple mathematical models for controlling COVID-19 transmission through social distancing and community awareness

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed S. Elgazzar
Keyword(s):  
Mathematical Models ◽  
Virus Transmission ◽  
Small World ◽  
Vaccination Rate ◽  
The Novel ◽  
Social Distancing ◽  
Community Awareness ◽  
Sufficient Degree ◽  
And Control

Abstract The novel COVID-19 pandemic is a current, major global health threat. Up till now, there is no fully approved pharmacological treatment or a vaccine. Also, its origin is still mysterious. In this study, simple mathematical models were employed to examine the dynamics of transmission and control of COVID-19 taking into consideration social distancing and community awareness. Both situations of homogeneous and nonhomogeneous population were considered. Based on the calculations, a sufficient degree of social distancing based on its reproductive ratio is found to be effective in controlling COVID-19, even in the absence of a vaccine. With a vaccine, social distancing minimizes the sufficient vaccination rate to control the disease. Community awareness also has a great impact in eradicating the virus transmission. The model is simulated on small-world networks and the role of social distancing in controlling the infection is explained.

scholarly journals Face coverings and respiratory tract droplet dispersion

2020 ◽  
Vol 7 (12) ◽  
pp. 201663
Author(s):  
Lucia Bandiera ◽  
Geethanjali Pavar ◽  
Gabriele Pisetta ◽  
Shuji Otomo ◽  
Enzo Mangano ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Uv Light ◽  
Laser Sheet ◽  
Virus Transmission ◽  
Single Layer ◽  
Social Distancing ◽  
Human Volunteers ◽  
Respiratory Droplets ◽  
Primary Transmission ◽  
Robust Evidence

Respiratory droplets are the primary transmission route for SARS-CoV-2, a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. We tested an anatomically realistic manikin head which ejected fluorescent droplets of water and human volunteers, in speaking and coughing conditions without a face covering, or with a surgical mask or a single-layer cotton face covering. We quantified the number of droplets in flight using laser sheet illumination and UV-light for those that had landed at table height at up to 2 m. For human volunteers, expiratory droplets were caught on a microscope slide 5 cm from the mouth. Whether manikin or human, wearing a face covering decreased the number of projected droplets by less than 1000-fold. We estimated that a person standing 2 m from someone coughing without a mask is exposed to over 10 000 times more respiratory droplets than from someone standing 0.5 m away wearing a basic single-layer mask. Our results indicate that face coverings show consistent efficacy at blocking respiratory droplets and thus provide an opportunity to moderate social distancing policies. However, the methodologies we employed mostly detect larger (non-aerosol) sized droplets. If the aerosol transmission is later determined to be a significant driver of infection, then our findings may overestimate the effectiveness of face coverings.

scholarly journals Evaluation of Technology-Supported Distance Measuring to Ensure Safe Aircraft Boarding during COVID-19 Pandemic

2020 ◽  
Vol 12 (20) ◽  
pp. 8724
Author(s):  
Paul Schwarzbach ◽  
Julia Engelbrecht ◽  
Albrecht Michler ◽  
Michael Schultz ◽  
Oliver Michler
Keyword(s):  
Three Dimensional ◽  
Virus Transmission ◽  
Distance Estimation ◽  
Signal Strength ◽  
Air Transport ◽  
Aircraft Cabins ◽  
Social Distancing ◽  
Simulation Based ◽  
Cabin Environment

With the rise of COVID-19, the sustainability of air transport is a major challenge, as there is limited space in aircraft cabins, resulting in a higher risk of virus transmission. In order to detect possible chains of infection, technology-supported apps are used for social distancing. These COVID-19 applications are based on the display of the received signal strength for distance estimation, which is strongly influenced by the spreading environment due to the signal multipath reception. Therefore, we evaluate the applicability of technology-based social distancing methods in an aircraft cabin environment using a radio propagation simulation based on a three-dimensional aircraft model. We demonstrate the susceptibility to errors of the conventional COVID-19 distance estimation, which can lead to large errors in the determination of distances and to the impracticability of traditional tracing approaches during passenger boarding/deboarding. In the context of the future connected cabin, a robust distance measurement must be implemented to ensure safe travel. Finally, our results can be transferred to similar fields of application, e.g., trains or public transport.

scholarly journals Air sampling by pumping through a filter: effects of air flow rate, concentration, and decay of airborne substances

2016 ◽  
Vol 67 (4) ◽  
pp. 326-331
Author(s):  
Marko Šoštarić ◽  
Branko Petrinec ◽  
Dinko Babić
Keyword(s):  
Time Dependence ◽  
Flow Rate ◽  
Particle Concentration ◽  
Air Flow ◽  
Airborne Particles ◽  
Air Flow Rate ◽  
General Applicability ◽  
Compact Expression ◽  
Filter Effects ◽  
Over Time

Abstract This paper tackles the issue of interpreting the number of airborne particles adsorbed on a filter through which a certain volume of sampled air has been pumped. This number is equal to the product of the pumped volume and particle concentration in air, but only if the concentration is constant over time and if there is no substance decomposition on the filter during sampling. If this is not the case, one must take into account the inconstancy of the concentration and the decay law for a given substance, which is complicated even further if the flow rate through the filter is not constant. In this paper, we develop a formalism which considers all of these factors, resulting in a single, compact expression of general applicability. The use of this expression is exemplified by addressing a case of sampling airborne radioactive matter, where the decay law is already well known. This law is combined with three experimentally observed time dependence of the flow rate and two models for the time dependence of the particle concentration. We also discuss the implications of these calculations for certain other situations of interest to environmental studies.

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