A brilliant and informative new thread by Dr Philip Lee debunking the anti-maskers’ nonsense and fake news about wearing face masks. During the coronavirus pandemic, more than ever, facts matter.

First published in July 2020.

I am seeing this paper quoted a lot about the harms potentially caused by masks.

Anti-masker tweeting about a 2015 study they don't seem to have understood. / Twitter - @AlexBerenson

So here we go, yes wearing a cloth mask as protection when you are working in a high exposure environment like a hospital is a bad idea.

But it is not as simple as that.

This trial aimed to see whether the use of simple cloth masks, in resource limited settings, is as effective as “medical masks”, that is a three layer non-woven mask (surgical mask), in a hospital.

The authors chose high exposure areas, in order presumably to best assess the level or risk. This included A&E, ICU, ID, and Respiratory wards.

This is important as many of these can be considered “Red Zones”, areas where high risk procedures generating aerosol are done.

U.S. National Institutes of Health

Also of importance, their control arm also involved mask wearing. In other words, whilst the intervention subjects wore masks for less than 70% of their shift, the control group was also wearing masks possibly for high risk procedures.

Their conclusion, cloth masks gathered more pathogens than medical masks, and more respiratory illnesses occurred.

Outcomes of the trials. / U.S. National Institutes of Health

But, of course, that is not the end of the story.

Cloth masks are generally made of one to two layers of fabric. But they are not designed to keep out droplets or external pathogens in a high exposure environment.

It is like wearing water wings to cross the channel. It is not the right tool for the job.

Wearing water wings to cross the channel... not the right tool for the job. / Pixabay

What the authors have shown is that in high exposure environment, where you are likely to be exposed to aerosols like in ICU, a cloth mask is of no use and in fact will trap pathogens.

The same does not apply when you are here: on a normal day, no one is being intubated in Lidl.

On a normal day, no one is being intubated in Lidl. / Geograph - David Dixon

In a lower exposure environment, a mask serves the simple purpose of preventing droplets spreading out when you speak, or cough.

It should not replace keeping as much distance as you can, and hand hygiene.

Dr Richard Davis is Clinical Microbiology Lab Director at Providence Sacred Heart, in Spokane, Washington, USA. / Twitter

“But then, shouldn’t we all wear surgical masks or FFP3?”

Good point, but the level of protection would be disproportionate to the risk, and exhaust valuable limited supplies of PPE.

You wouldn’t dress like this to ride a bicycle to the shops, or for a Nerf fight:

You wouldn’t dress this way to ride a bicycle to the shops, or for a Nerf fight. / Pixabay

Cloth masks/face covering are the best measures to reduce the spread of droplets from an asymptomatic individual, if we do not want to return to the lockdowns of April, or more draconian measures.

In conclusion, if you are working in ICU or A&E, wear appropriate PPE. If you are going to Aldi, Waitrose, or your local furniture shop, wear the goddamn cloth face covering!🔷

Wear the goddamn cloth face covering! / Pixabay

[This piece was first published as a Twitter thread and turned into the above article on 15 July 2020 with the purpose of reaching a larger audience. It has been minorly edited and corrected, and published with the author’s consent. | The author of the tweets writes in a personal capacity.]

(Cover: Pixbay.)

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