"When the COVID-19 pandemic took off in 2020, so too
did questions over the effectiveness of wearing a face
mask to prevent the spread of the virus. Now, four
years later, what does the science say?
In an interview for 60 Minutes, CBS News chief medical
correspondent Dr. Jon LaPook posed that question to
Linsey Marr, a Virginia Tech university professor
specializing in aerosol science.
"They are very helpful in reducing the chances that the
person will get COVID because it's reducing the amount
of virus that you would inhale from the air around
you," Marr said about masks.
No mask is 100% effective. An N95, for example, is
named as such because it is at least 95% efficient at
blocking airborne particles when used properly. But
even if a mask has an 80% efficiency, Marr said, it
still offers meaningful protection.
"That greatly reduces the chance that I'm going to
become infected," Marr said.
Marr said research shows that high-quality masks can
block particles that are the same size as those
carrying the coronavirus. Masks work, she explained, as
a filter, not as a sieve. Virus particles must weave
around the layers of fibers, and as they do so, they
may crash into those fibers and become trapped.
Marr likened it to running through a forest of trees.
Walk slowly, and the surrounding is easy to navigate.
But being forced through a forest at a high speed
increases the likelihood of running into a tree.
"Masks, even cloth masks, do something," she said.
Early in the pandemic, some guidance from health
professionals suggested that wearing a mask might
actually lead to infection: A person might encounter a
contaminated mask and then touch their eyes, nose, or
mouth. But research in the ensuing years has shown that
fear to be misplaced.
"There wasn't any evidence really that that happens,"
Marr said.
Marr said her team aerosolized the coronavirus, pulled
it through a mask, and then examined how much virus
survived on the mask. The study reported some viral
particle remained on some cloth masks, but no virus
survived on the N95s or surgical masks.
Marr's team also touched artificial skin to masks and
looked at how many virus particles transferred to the
artificial skin. No infectious virus transferred.
"I hope the study kind of shows that it's something we
don't need to worry about as much as we were told,"
Marr said.
|
|