COVID-19 Latest: Studies Show That Exhaled 'Aerosols' Spread SARS-CoV-2 Virus Up To 4 Meters And Footwear Also Help Transmit The Disease
: New emerging studies show that individuals infected with the SARS-CoV02 coronavirus could be spreading "aerosolized" viral particles as they cough, breathe or talk in a 13-foot radius, and viral particles can also move around on people's shoes.
Fortunately the studies also indicated that standard protective gear appears to effectively shield health care workers from these aerosolized droplets and infection, and even cloth face masks could curb the spread of exhaled droplets.
Emergency medicine physician Dr. Robert Glatter sadi that the findings are a reminder that any form of social distancing should help curb new cases of COVID-19.
Dr Glatter who is from the Lenox Hill Hospital in New York City said, "The bottom line is that maintaining some distance from others is better than none. Six feet is better than 5 feet. In the age of coronavirus, the more the better. It really comes down to the likelihood of viral transmission."
In the first study, Chinese researchers tracked viral "distribution" in hospital wards in Wuhan, the city where the coronavirus pandemic emerged, from February 19 to March 2. The research was published in the US CDC’s Journal of Emerging Infectious Diseases
Dr Zhen-Dong Guo, of the Academy of Military Medical Sciences in Beijing, who is the research leader said, "We collected swab samples from potentially contaminated objects in the ICU and general ward. We also sampled indoor air and the air outlets to detect aerosol exposure."
The researchers observed that when people exhale, heavier droplets (potentially containing virus) tend to drop to the ground because of gravity, whereas lighter droplets can remain suspended in breathable air.
The researcher’s tests found that 70% of swab samples from the hospital floor came up positive for coronavirus, "perhaps because of gravity and air flow causing most virus droplets to float to the ground," the study authors said.
The researchers added, "In addition, as medical staff walk around the ward, the virus can be tracked all over the floor, as indicated by the 100% rate of positivity from the floor in the hospital pharmacy, where there were no patients. Therefore, the soles of medical staff shoes might function as carriers."
As expected, swabs taken of often-touched surfaces such as doorknobs, bed rails, trash cans and computer mice all typically came up positive for coronavirus.
Dr Guo said, “As for what about the air people breathe, the closer to an infected patient, the more likely an air sample was to come up positive. Virus-laden aerosols were mainly concentrated near and downstream from the patients."
It was observed that the tiny airborne aerosols could travel farther than the 6 feet now recommended in most social distancing advisories. In fact, "the maximum transmission distance of coronavirus aerosol might be 4 meters (13 feet)," the researchers
The research study did have one good piece of news: Protective gear worn by hospital staff appears to thwart viral infection. "As of March 30, no staff members at Huoshenshan Hospital had been infected," despite widespread contamination of air and surfaces, the team noted.
In yet another study of the aerosolization of exhaled droplets that was published in the New England Journal of Medicine
, a team from the U.S. National Institutes of Health and the University of Pennsylvania used "laser light scattering" technology to track the dispersion of droplets from the mouth during normal speech. https://www.nejm.org/doi/full/10.1056/NEJMc2009324?query=featured_coronavirus
The medical researchers found that droplets were dispersed into the air, but wearing a "slightly damp washcloth over the speaker's mouth" effectively stopped most of the dispersion.
Harvard University molecular biologist Dr Matthew Meselson in a related commentary on that study said, "The findings suggests the advisability of wearing a suitable mask whenever it is thought that infected persons may be nearby."
Dr Glatter added, "While 6 feet is certainly ideal based on recommendations by the U.S. Centers for Disease Control and Prevention, we are now learning that aerosolized droplets from coughing or sneezing, which may then be carried by currents indoors and outside, may make this distance less than ideal."
However he conceded that the science on all of this continues to evolve.
He said, "The truth is this, we don't know what it truly takes to get infected with the virus, including the amount of virus necessary to actually initiate an infection. In fact, it may not require infected surfaces or droplets after all, just aerosols. We just don't know. Research on this concept continues to expand and evolve."
Dr Glatter stressed that other factors including how deeply into the lungs viral particles penetrate, and the strength of a person's immune system are also involved in the infection process.
Another physician, Dr Eric Cioe Pena from Northwell Health in New Hyde Park, New York commented over the Chinese study, he agreed that "the potential for this virus to spread via aerosols is particularly scary, because it's essentially a hybrid between an airborne and a droplet virus, and that the droplets are able to hang out in the air for an extensive period of time and potentially infect other people."
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