COVID-19 virus is evolving to get better at becoming airborne, new study
shows
Study suggests need for better ventilation and tight-fitting masks, in addition to widespread vaccination to help stop spread of the virus

Date:
September 16, 2021
Source:
University of Maryland
Summary:
A new study finds that SARS-CoV-2 is evolving toward more efficient
aerosol generation, and loose-fitting masks provide significant
but only modest source control. Until vaccination rates are very
high, continued layered controls, including improved ventilation,
increased filtration, UV air sanitation, and tight-fitting masks
are critical to protect people in public-facing jobs and indoor
spaces, researchers urge.



FULL STORY ========================================================================== Results of a new study led by the University of Maryland School of Public Health show that people infected with the virus that causes COVID-19
exhale infectious virus in their breath -- and those infected with the
Alpha variant (the dominant strain circulating at the time this study
was conducted) put 43 to 100 times more virus into the air than people
infected with the original strains of the virus. The researchers also
found that loose-fitting cloth and surgical masks reduced the amount of
virus that gets into the air around infected people by about half. The
study was published in Clinical Infectious Diseases.


==========================================================================
"Our latest study provides further evidence of the importance of airborne transmission," said Dr. Don Milton, professor of environmental health at
the University of Maryland School of Public Health (UMD SPH). "We know
that the Delta variant circulating now is even more contagious than the
Alpha variant.

Our research indicates that the variants just keep getting better at
travelling through the air, so we must provide better ventilation and
wear tight-fitting masks, in addition to vaccination, to help stop spread
of the virus." The amount of virus in the air coming from Alpha variant infections was much more -- 18-times more -- than could be explained by
the increased amounts of virus in nasal swabs and saliva. One of the
lead authors, doctoral student Jianyu Lai explained that, "We already
knew that virus in saliva and nasal swabs was increased in Alpha variant infections. Virus from the nose and mouth might be transmitted by sprays
of large droplets up close to an infected person. But, our study shows
that the virus in exhaled aerosols is increasing even more." These major increases in airborne virus from Alpha infections occurred before the
Delta variant arrived and indicate that the virus is evolving to be
better at travelling through the air.

To test whether face masks work in blocking the virus from being
transmitted among people, this study measured how much SARS-CoV-2 is
breathed into the air and tested how much less virus people sick with
COVID-19 exhaled into the air after putting on a cloth or surgical
mask. Face coverings significantly reduced virus-laden particles in
the air around the person with COVID-19, cutting the amount by about
50%. Unfortunately, the loose-fitting cloth and surgical masks didn't
stop infectious virus from getting into the air.

Dr. Jennifer German, a co-author said, "The take-home messages from this
paper are that the coronavirus can be in your exhaled breath, is getting
better at being in your exhaled breath, and using a mask reduces the
chance of you breathing it on others." This means that a layered approach
to control measures (including improved ventilation, increased filtration,
UV air sanitation, and tight-fitting masks, in addition to vaccination)
is critical to protect people in public-facing jobs and indoor spaces.

The study, Infectious SARS-CoV-2 in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection, was published in Clinical Infectious Diseases
and conducted by researchers from the University of Maryland School of
Public Health, University of Maryland School of Medicine, Walter Reed
Army Institute of Research, Duke-NUS Medical School, and Rice University.

========================================================================== Story Source: Materials provided by University_of_Maryland. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Oluwasanmi O Adenaiye, Jianyu Lai, P Jacob Bueno de Mesquita,
Filbert
Hong, Somayeh Youssefi, Jennifer German, S-H Sheldon Tai, Barbara
Albert, Maria Schanz, Stuart Weston, Jun Hang, Christian Fung,
Hye Kyung Chung, Kristen K Coleman, Nicolae Sapoval, Todd Treangen,
Irina Maljkovic Berry, Kristin Mullins, Matthew Frieman, Tianzhou
Ma, Donald K Milton.

Infectious SARS-CoV-2 in Exhaled Aerosols and Efficacy of Masks
During Early Mild Infection. Clinical Infectious Diseases, 2021;
DOI: 10.1093/ cid/ciab797 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210916173428.htm

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