Face Mask Disrupts trajectory of cough New York Times April 14 2020
But as this simulation suggests, and scientists have argued, droplets can travel farther than six feet. And small droplets known as aerosols can remain suspended or travel through the air before they eventually settle on surfaces. This is how they could disperse over the next 20 minutes.
The Centers for Disease Control and Prevention encourages people to stay home. If you must venture out, you should stay at least six feet away from others. The World Health Organization recommends a minimum of three feet of separation.
Scientists are learning about the novel coronavirus in real time, and those who study similar respiratory illnesses say that until it is better understood, no guideline is likely to offer perfect safety. Instead, understanding the possible transmission routes for the virus can help us see why keeping our distance is so important.
From web post by Michael B. Edmond (April 11, 2020):
Our goal should be to have a face shield for every person in the country. It should be worn anytime a person leaves their home, while in any public place, and even at work. From news reports, it appears that face shields are already being more commonly worn in other nations, particularly in some Asian countries.
The advantages of face shields are their durability allowing them to be worn an indefinite number of times, the ability to easily clean them after use, their comfort, and they prevent the wearer from touching their face. Importantly, they cover all the portals of entry for this virus–the eyes, the nose, and the mouth. Moreover, the supply chain is significantly more diversified than that of face masks, so availability is much greater.
Some are critical of any strategy that isn’t perfect. But let’s think about the influenza vaccine. Although the effectiveness varies from year to year, on average it’s 40%. We push this vaccine hard in the hospital and in the community. Could we expect that face shields are at least 40% effective in reducing the transmission of COVID-19? I think so. Universal shielding would bend the curve more quickly and accelerate the ability to reduce social distancing and restrictions on movement.
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Face shields are a simple solution that if implemented universally would have a major impact on public health. Until we have a vaccine, this may be our best intervention for preventing transmission in the community.
Michael B. Edmond, MD, MPH, MPA, MBA is the Chief Quality Officer and Associate Chief Medical Officer for University of Iowa Health Care and Clinical Professor of Infectious Diseases at the University of Iowa Carver College of Medicine. He previously served as the Richard P. Wenzel Professor of Internal Medicine, Chair of the Division of Infectious Diseases, and Hospital Epidemiologist at Virginia Commonwealth University in Richmond.
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