Face masks are emerging as one of the most powerful weapons to fight the novel coronavirus, with growing evidence that facial coverings help prevent transmission—even if an infected wearer is in close contact with others.
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Face masks are emerging as one of the most powerful weapons to
fight the novel coronavirus, with growing evidence that facial coverings help prevent transmission—even if an infected wearer is in close contact with others.
Robert Redfield, director of the Centers for Disease Control and Prevention, said he believes the pandemic could be brought under control over the next four to eight weeks if “we could get everybody to wear a mask right now.” His comments, made Tuesday with the Journal of the American Medical Association, followed an
editorial he and others wrote there emphasizing “ample evidence” of asymptomatic spread and highlighting new studies showing how masks help reduce transmission.
The research Dr. Redfield cited included a
newly published study suggesting that universal use of surgical masks helped reduce rates of confirmed Covid-19 infections among health-care workers at the Mass General Brigham health-care system in Massachusetts.
*Researchers found that, of the masks they studied, a stitched, double-layered cotton mask was most effective in preventing droplets from being emitted forward. Most of the escape was from the gap between the nose and mask. Droplets traveled further out of the cone mask and also escaped from the top edge.
His comments are the clearest message yet from the CDC, amid fierce debate over facial coverings, fueled initially by shifting messages from federal and global officials about their necessity and then by those espousing individual liberties.
Researchers from around the world have found wearing even a basic cloth face covering is more effective in reducing the spread of Covid-19 than wearing nothing at all. And many are now examining the possibility that masks might offer some personal protection from the virus, despite initial thinking that they mostly protect others.
Experts caution that widespread masking doesn’t eliminate the need to follow other recommendations, like frequent handwashing and social distancing.
In the absence of widespread availability of N95 masks—
considered among the most effectivebut typically reserved for health-care workers—transmission can still be reduced with simple and affordable face coverings, the research shows. In a study published last month in the journal Physics of Fluids,
researchers at Florida Atlantic University found that, of the readily accessible facial coverings they studied, a well-fitted homemade stitched mask comprising two layers of cotton quilting fabric was most effective for reducing the forward spread of droplets. The research was conducted using a mannequin’s head, an air compressor and a smoke generator that mechanically simulated a cough.
The study found that aerosol-size droplets expelled from the mannequin with the double-layered cotton mask traveled forward about 2.5 inches on average, and that most of the leakage escaped from gaps between the nose and face. Loosely fitting facial coverings, including a folded cotton handkerchief with ear loops, as well as a bandanna were less helpful, the study found. With those masks, droplets traveled on average about 1.25 and 3.5 feet, respectively. In contrast, the study found droplets traveled about 8 inches on average with an off-the-shelf cone-shaped mask.
Meanwhile, droplets from an uncovered cough traveled around 8 feet on average, though the study found that they could travel up to 12 feet—double the currently recommended social-distancing guideline of 6 feet. Leakage from a common disposable surgical mask wasn’t studied, though two of the study’s authors, Siddhartha Verma and Manhar Dhanak, said they are working on it.
“It was surprising in a good way to see that a homemade mask could do so well…that we don’t have to get a very fancy mask,” Dr. Verma said. “A cotton mask can be washed at home and dried. Reusability is becoming important as we go into this for the long haul.”
They are also in the process of putting a laboratory apparatus together to test how much protection various masks might offer to the person wearing them.
The amount of virus exposure might influence degree of sickness, according to a review of viral literature and Covid-19 epidemiology by Monica Gandhi, a professor of medicine at the University of California, San Francisco. She and her co-authors posit in the research, expected to be published this month in the Journal of General Internal Medicine, that masks provide an important barrier and could lead to a milder infection or even prevent one altogether. While cloth and surgical masks can widely vary, she believes some masks can likely filter out a majority of large viral droplets.
Amy Price, a senior research scientist at Stanford’s Anesthesia Informatics and Media Lab, maintains, in contrast, that the primary benefit of wearing a mask is to protect others and reduce Covid-19 transmission. She believes that, excluding N95 masks, multilayered masks with a slightly waterproof outer layer best minimize spread. She said rubbing the outer layer of the mask with a latex glove before donning it creates static electricity—which Stanford researchers believe can better
Face masks are emerging as one of the most powerful weapons to
fight the novel coronavirus, with growing evidence that facial coverings help prevent transmission—even if an infected wearer is in close contact with others.
Robert Redfield, director of the Centers for Disease Control and Prevention, said he believes the pandemic could be brought under control over the next four to eight weeks if “we could get everybody to wear a mask right now.” His comments, made Tuesday with the Journal of the American Medical Association, followed an
editorial he and others wrote there emphasizing “ample evidence” of asymptomatic spread and highlighting new studies showing how masks help reduce transmission.
The research Dr. Redfield cited included a
newly published study suggesting that universal use of surgical masks helped reduce rates of confirmed Covid-19 infections among health-care workers at the Mass General Brigham health-care system in Massachusetts.
*Researchers found that, of the masks they studied, a stitched, double-layered cotton mask was most effective in preventing droplets from being emitted forward. Most of the escape was from the gap between the nose and mask. Droplets traveled further out of the cone mask and also escaped from the top edge.
His comments are the clearest message yet from the CDC, amid fierce debate over facial coverings, fueled initially by shifting messages from federal and global officials about their necessity and then by those espousing individual liberties.
Researchers from around the world have found wearing even a basic cloth face covering is more effective in reducing the spread of Covid-19 than wearing nothing at all. And many are now examining the possibility that masks might offer some personal protection from the virus, despite initial thinking that they mostly protect others.
Experts caution that widespread masking doesn’t eliminate the need to follow other recommendations, like frequent handwashing and social distancing.
In the absence of widespread availability of N95 masks—
considered among the most effectivebut typically reserved for health-care workers—transmission can still be reduced with simple and affordable face coverings, the research shows. In a study published last month in the journal Physics of Fluids,
researchers at Florida Atlantic University found that, of the readily accessible facial coverings they studied, a well-fitted homemade stitched mask comprising two layers of cotton quilting fabric was most effective for reducing the forward spread of droplets. The research was conducted using a mannequin’s head, an air compressor and a smoke generator that mechanically simulated a cough.
The study found that aerosol-size droplets expelled from the mannequin with the double-layered cotton mask traveled forward about 2.5 inches on average, and that most of the leakage escaped from gaps between the nose and face. Loosely fitting facial coverings, including a folded cotton handkerchief with ear loops, as well as a bandanna were less helpful, the study found. With those masks, droplets traveled on average about 1.25 and 3.5 feet, respectively. In contrast, the study found droplets traveled about 8 inches on average with an off-the-shelf cone-shaped mask.
Meanwhile, droplets from an uncovered cough traveled around 8 feet on average, though the study found that they could travel up to 12 feet—double the currently recommended social-distancing guideline of 6 feet. Leakage from a common disposable surgical mask wasn’t studied, though two of the study’s authors, Siddhartha Verma and Manhar Dhanak, said they are working on it........click above to read more.
