Both surgical and cotton masks were found to be ineffective for preventing the dissemination of SARS-CoV-2 from the coughs of patients with COVID-19. A study conducted at two hospitals in Seoul, South Korea, found that when COVID-19 patients coughed into either type of mask, droplets of virus were released to the environment and external mask surface. A brief research report is published in Annals of Internal Medicine.
During respiratory viral infection, face masks are thought to prevent transmission, leading health care experts to recommend their use during the COVID-19 pandemic. With a shortage of both N95 and surgical masks, which have been shown to prevent the spread of influenza virus, cotton masks have gained interest as a substitute. However, it is not known if surgical or cotton masks worn by patients with COVID-19 prevent contamination of the environment.
Researchers from Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea instructed 4 patients with COVID-19 to cough 5 times each onto a petri dish while wearing the following sequence of masks: no mask, surgical mask, cotton mask, and again with no mask. Mask surfaces were swabbed with aseptic Dacron swabs in the following sequence: outer surface of surgical mask, inner surface of surgical mask, outer surface of cotton mask, and inner surface of cotton mask. The researchers found SARS COV-2 on all surfaces. These findings suggest that recommendations to wear face masks to prevent the spread of COVID-19 may not be effective.
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4 thoughts on “Neither surgical nor cotton masks effectively filter SARS COV-2: Study”
They’re not supposed to “filter” 100%, which is what a petri dish would demonstrate. They’re supposed to provide resistance so it’s not projected as far and to reduce viral load.
It’s not a black and white thing like that.
Why is the science so opposed to a simple way to reduce but not eliminate spread? So opposed that information is presented in a misleading manner. I do not understand this. It’s not like a vaccine exists. It’s not like everyone can stay home, and stay home forever. This is getting absolutely absurd.
Exactly, Jou. Thank you.
This experiment is done with a forceful cough. We know that a forceful cough or sneeze is not the only way the virus is disseminated. Simply breathing or talking can spread viral particles as well. We know that many people who are positive are asymptomatic. They will not be exhibiting forceful coughs or sneezing.
A mask can reduce the amount of particles that are released into the environment. And without the velocity of a cough, likely retain viral particles within the mask.
As well, any reduction in viral particles will help. As we have seen the severity Covid-19 can be worse for those exposed to a higher viral load. As we see with healthcare providers.
The fewer particles disseminated, the fewer viral particles in the environment.
The hypothesis made in this article is extremely weak.
How close was the Petri dish held to the patients face? What was the velocity of the cough? What is the viral count on the Petri dish? Did the Petri dish have medium and were viral particles allowed to replicate? Or was it a clean surface?
The scientists also neglected to mention that masks help to reduce transmission via touch.
Human beings naturally touch their eyes, nose, and mouth; human beings touch their faces thousands of times a day without being cognizant of it.
In a home environment that is sanitized, this may not be a problem unless there is an infected individual residing in the home.
In public spaces, this is a tremendous risk. A mask effectively stops a person from touching their mouth and nose in public and reduces the chance of introducing viral particles.
I recommend eye protection as well when out. Even simple glasses to prevent touching ones eyes.
This is an extremely irresponsible study conclusion to publish during these times.
Masks are absolutely beneficial.
In a rush to make name/fame, they lost their brain to think about the logic, and common sense.