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Why leaving your nose uncovered defeats the purpose of wearing a mask

Research suggests covering nose is critical to preventing spread of COVID-19

DETROIT – What is the correct way to wear a mask to prevent the spread of the coronavirus (COVID-19)? Many people wear it pulled down below their nose, but does that defeat the purpose of wearing a mask at all?

While masks protect the wearer from COVID-19 to some degree, their primary purpose is “source control,” or limiting the amount of infectious droplets coming out of the wearer’s respiratory tract -- both the mouth and nose.

Most people usually breathe through their noses -- and for good reason. People smell through their noses, which warm and humidify the air we breathe. Noses help filter out debris and micro organisms in the air.

Breathing out through the nose is also healthier. It naturally improves lung and circulatory function and gives the body a chance to reclaim some of the warmth and humidity you would otherwise exhale into the environment.

Unfortunately, relative to spreading COVID-19, the nose also appears to be at an advantage over the mouth. A recent published study mapped locations in the respiratory tract where the virus most quickly invades, replicates and spreads.

Researchers found the cells that line the nose were significantly more likely to become infected and shed virus compared to the throat or lungs.

That means every time a person exhales through their nose, they’re likely generating a higher concentration of infections aerosol than if they were breathing through their mouth.

It also means in order to block that infectious cloud from escaping to infect other people, it’s just as important to cover your nose with a mask.

Another interesting thought generated by the study addresses the question of how the SARS-CoV-2 virus even infects people’s lungs to begin with. Researchers suggested based on their findings that the virus doesn’t get to the lungs through the blood or by sequentially marching lower down the respiratory tract.

Researchers believe the virus simply jumps to the lungs from infected nasal secretions that a susceptible person aspirates or inhales.


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