Exactly why are surgical masks not useful?

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sTeamTraen
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Exactly why are surgical masks not useful?

Post by sTeamTraen » Wed Mar 18, 2020 12:07 pm

The official line (note: those words are not intended to be read in a tin-foil hat tone of voice) is that wearing a surgical mask like what your dentist uses helps to protect people from the wearer, but doesn't protect the wearer themselves. Since I presume that most of the substantial number of people I am seeing on the streets round here don't currently have symptoms, I guess they are not convinced by this advice. (Some people without masks are wrapping a scarf around their face or getting creative with their hijab.)

Some arguments I can think of both ways:

Pro: You will mechanically touch your nose and mouth less with your fingers if there is a mask in front of them.
Con: There are lots of leaks round the sides.
Pro: If someone coughs right in your face, less of the droplets will hit your mucous membranes, shirley.
Con: If the above happens, you will be getting a hit of evaporating droplet contents on every breath until you change the mask.

Is there any actual research on this, or is it all just argument from theory, diagrams, and people on the Internet doing badly controlled thought experiments?

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Re: Exactly why are surgical masks not useful?

Post by Pucksoppet » Wed Mar 18, 2020 12:31 pm

sTeamTraen wrote:
Wed Mar 18, 2020 12:07 pm
The official line (note: those words are not intended to be read in a tin-foil hat tone of voice) is that wearing a surgical mask like what your dentist uses helps to protect people from the wearer, but doesn't protect the wearer themselves. Since I presume that most of the substantial number of people I am seeing on the streets round here don't currently have symptoms, I guess they are not convinced by this advice. (Some people without masks are wrapping a scarf around their face or getting creative with their hijab.)

Some arguments I can think of both ways:

Pro: You will mechanically touch your nose and mouth less with your fingers if there is a mask in front of them.
Con: There are lots of leaks round the sides.
Pro: If someone coughs right in your face, less of the droplets will hit your mucous membranes, shirley.
Con: If the above happens, you will be getting a hit of evaporating droplet contents on every breath until you change the mask.

Is there any actual research on this, or is it all just argument from theory, diagrams, and people on the Internet doing badly controlled thought experiments?
Frankly, I wish the last dentist I saw did wear a mask. Spoiler:


But to answer your question, no idea.

I have seen designs of respirator equipment that maintain a positive airflow, powered by a belt-worn fan that puts the airflow through a HEPA filter and pushes the air up a flexible tube to the mask. That keeps the mask dry, stops CO2 build-up, and makes the HEPA filter easier to mass produce. They are used by commercial painters etc. The masks are typically full-face. That kind of set up probably works to protect the wearer.

This randomly found website article is very dismissive of surgical masks:

Infection Control Today (2009-01-29): How to Evaluate Respirators
Surgical masks offer the patient protection from liquid droplets coming from the healthcare worker but since they are not respirators they do not offer the healthcare worker (HCW) any respiratory protection against infectious airborne particles such as SARS, TB or various types of influenza.
ETA: Walking around with the 'cape' hood of this one would probably give you adequate protection

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Gentleman Jim
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Re: Exactly why are surgical masks not useful?

Post by Gentleman Jim » Wed Mar 18, 2020 1:02 pm

Pucksoppet wrote:
Wed Mar 18, 2020 12:31 pm
ETA: Walking around with the 'cape' hood of this one would probably give you adequate protection

From experience, even with full airflow from an air line, they get very very hot inside (think personal head sauna).
I can imagine the airflow from a battery model would be even less
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Re: Exactly why are surgical masks not useful?

Post by Pucksoppet » Wed Mar 18, 2020 1:30 pm

Gentleman Jim wrote:
Wed Mar 18, 2020 1:02 pm
Pucksoppet wrote:
Wed Mar 18, 2020 12:31 pm
ETA: Walking around with the 'cape' hood of this one would probably give you adequate protection

From experience, even with full airflow from an air line, they get very very hot inside (think personal head sauna).
I can imagine the airflow from a battery model would be even less
Thank you for the voice of experience.

In other news, this article is positive:

Infection Control Today (2020-03-13): Study: Infection Preventionists’ Risk of Getting COVID-19 Might Not Be as Great as Feared
...what happened to 11 healthcare workers at the Queen Mary Hospital who, without proper personal protective equipment (PPE), treated patients confirmed to have COVID-19. Answer? Nothing. That is, the 11 healthcare workers—who had to be quarantined for 14 days—did not contract COVID-19.

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Re: Exactly why are surgical masks not useful?

Post by Woodchopper » Wed Mar 18, 2020 2:21 pm

sTeamTraen wrote:
Wed Mar 18, 2020 12:07 pm
The official line (note: those words are not intended to be read in a tin-foil hat tone of voice) is that wearing a surgical mask like what your dentist uses helps to protect people from the wearer, but doesn't protect the wearer themselves. Since I presume that most of the substantial number of people I am seeing on the streets round here don't currently have symptoms, I guess they are not convinced by this advice. (Some people without masks are wrapping a scarf around their face or getting creative with their hijab.)

Some arguments I can think of both ways:

Pro: You will mechanically touch your nose and mouth less with your fingers if there is a mask in front of them.
Con: There are lots of leaks round the sides.
Pro: If someone coughs right in your face, less of the droplets will hit your mucous membranes, shirley.
Con: If the above happens, you will be getting a hit of evaporating droplet contents on every breath until you change the mask.

Is there any actual research on this, or is it all just argument from theory, diagrams, and people on the Internet doing badly controlled thought experiments?
Here’s the WHO guidance: https://www.who.int/emergencies/disease ... -use-masks

It’s a bit different from the above, but doesn’t cite research.

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Re: Exactly why are surgical masks not useful?

Post by science_fox » Wed Mar 18, 2020 2:37 pm

sTeamTraen wrote:
Wed Mar 18, 2020 12:07 pm
The official line (note: those words are not intended to be read in a tin-foil hat tone of voice) is that wearing a surgical mask like what your dentist uses helps to protect people from the wearer, but doesn't protect the wearer themselves. Since I presume that most of the substantial number of people I am seeing on the streets round here don't currently have symptoms, I guess they are not convinced by this advice. (Some people without masks are wrapping a scarf around their face or getting creative with their hijab.)

Some arguments I can think of both ways:

Pro: You will mechanically touch your nose and mouth less with your fingers if there is a mask in front of them.
Con: There are lots of leaks round the sides.
Pro: If someone coughs right in your face, less of the droplets will hit your mucous membranes, shirley.
Con: If the above happens, you will be getting a hit of evaporating droplet contents on every breath until you change the mask.

Is there any actual research on this, or is it all just argument from theory, diagrams, and people on the Internet doing badly controlled thought experiments?
There's a line in last week's new scientist (I hope rather than expect to be research based) that you touch your face a lot more continually adjusting the fit, especially close to the eyes. They're nowhere near tight enough to prevent virus particles getting through.

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Re: Exactly why are surgical masks not useful?

Post by basementer » Wed Mar 18, 2020 2:44 pm

Pucksoppet wrote:
Wed Mar 18, 2020 1:30 pm
Gentleman Jim wrote:
Wed Mar 18, 2020 1:02 pm
Pucksoppet wrote:
Wed Mar 18, 2020 12:31 pm
ETA: Walking around with the 'cape' hood of this one would probably give you adequate protection

From experience, even with full airflow from an air line, they get very very hot inside (think personal head sauna).
I can imagine the airflow from a battery model would be even less
Thank you for the voice of experience.

In other news, this article is positive:

Infection Control Today (2020-03-13): Study: Infection Preventionists’ Risk of Getting COVID-19 Might Not Be as Great as Feared
...what happened to 11 healthcare workers at the Queen Mary Hospital who, without proper personal protective equipment (PPE), treated patients confirmed to have COVID-19. Answer? Nothing. That is, the 11 healthcare workers—who had to be quarantined for 14 days—did not contract COVID-19.
Something about that website feels wrong, but maybe it's just that it's built by someone whose first language isn't English. Anyway, the paper they cite is https://www.cambridge.org/core/journals ... DC747EB6EC which actually says that of 413 workers who came into contact with those patients, a small number, 11, were thought to have had inadequate protection, so they were isolated but luckily they hadn't caught the virus.
I'll think of something.

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Re: Exactly why are surgical masks not useful?

Post by Pucksoppet » Wed Mar 18, 2020 3:52 pm

basementer wrote:
Wed Mar 18, 2020 2:44 pm
Pucksoppet wrote:
Wed Mar 18, 2020 1:30 pm
Gentleman Jim wrote:
Wed Mar 18, 2020 1:02 pm



From experience, even with full airflow from an air line, they get very very hot inside (think personal head sauna).
I can imagine the airflow from a battery model would be even less
Thank you for the voice of experience.

In other news, this article is positive:

Infection Control Today (2020-03-13): Study: Infection Preventionists’ Risk of Getting COVID-19 Might Not Be as Great as Feared
...what happened to 11 healthcare workers at the Queen Mary Hospital who, without proper personal protective equipment (PPE), treated patients confirmed to have COVID-19. Answer? Nothing. That is, the 11 healthcare workers—who had to be quarantined for 14 days—did not contract COVID-19.
Something about that website feels wrong, but maybe it's just that it's built by someone whose first language isn't English. Anyway, the paper they cite is https://www.cambridge.org/core/journals ... DC747EB6EC which actually says that of 413 workers who came into contact with those patients, a small number, 11, were thought to have had inadequate protection, so they were isolated but luckily they hadn't caught the virus.
Thanks for that.

I was just trying to find a note of less-black news in amongst all the doom-and-gloom.

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Re: Exactly why are surgical masks not useful?

Post by Pucksoppet » Wed Mar 18, 2020 3:56 pm

Woodchopper wrote:
Wed Mar 18, 2020 2:21 pm

Here’s the WHO guidance: https://www.who.int/emergencies/disease ... -use-masks

It’s a bit different from the above, but doesn’t cite research.
And I wonder how many people will do:
  • Before putting on a mask, clean hands with alcohol-based hand rub or soap and water.
  • Cover mouth and nose with mask and make sure there are no gaps between your face and the mask.
  • Avoid touching the mask while using it; if you do, clean your hands with alcohol-based hand rub or soap and water.
  • Replace the mask with a new one as soon as it is damp and do not re-use single-use masks.
  • To remove the mask: remove it from behind (do not touch the front of mask); discard immediately in a closed bin; clean hands with alcohol-based hand rub or soap and water.

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Re: Exactly why are surgical masks not useful?

Post by Bird on a Fire » Wed Mar 18, 2020 4:01 pm

Pucksoppet wrote:
Wed Mar 18, 2020 3:56 pm
And I wonder how many people will do:
  • Before putting on a mask, clean hands with alcohol-based hand rub or soap and water.
  • Cover mouth and nose with mask and make sure there are no gaps between your face and the mask.
  • Avoid touching the mask while using it; if you do, clean your hands with alcohol-based hand rub or soap and water.
  • Replace the mask with a new one as soon as it is damp and do not re-use single-use masks.
  • To remove the mask: remove it from behind (do not touch the front of mask); discard immediately in a closed bin; clean hands with alcohol-based hand rub or soap and water.
I think part of the push against widespread public use of masks was to preserve the limited supply for those that both really need them and can be relied upon to use them correctly - e.g., medical staff.

People shouldn't be wearing them just to go shopping or whatever when they could just socially distance, and will probably go around touching a bunch of stuff and getting close to people and then fiddling with their masks.
"Ecology without socialism is just gardening" - Chico Mendes

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Re: Exactly why are surgical masks not useful?

Post by Woodchopper » Wed Mar 18, 2020 4:07 pm

Bird on a Fire wrote:
Wed Mar 18, 2020 4:01 pm
Pucksoppet wrote:
Wed Mar 18, 2020 3:56 pm
And I wonder how many people will do:
  • Before putting on a mask, clean hands with alcohol-based hand rub or soap and water.
  • Cover mouth and nose with mask and make sure there are no gaps between your face and the mask.
  • Avoid touching the mask while using it; if you do, clean your hands with alcohol-based hand rub or soap and water.
  • Replace the mask with a new one as soon as it is damp and do not re-use single-use masks.
  • To remove the mask: remove it from behind (do not touch the front of mask); discard immediately in a closed bin; clean hands with alcohol-based hand rub or soap and water.
I think part of the push against widespread public use of masks was to preserve the limited supply for those that both really need them and can be relied upon to use them correctly - e.g., medical staff.

People shouldn't be wearing them just to go shopping or whatever when they could just socially distance, and will probably go around touching a bunch of stuff and getting close to people and then fiddling with their masks.
Yes, indeed. Masks can be effective, but only when worn by people who know how to use them.

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Re: Exactly why are surgical masks not useful?

Post by Gentleman Jim » Wed Mar 18, 2020 4:17 pm

Woodchopper wrote:
Wed Mar 18, 2020 4:07 pm
Yes, indeed. Masks can be effective, but only when worn by people who know how to use them.
Which, ironically, may not be doctors and nurses.
If you really want to be trained to use them properly, contact someone who works in a pharmaceutical clean room, or even better, a microprocessor type manufacturer
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Re: Exactly why are surgical masks not useful?

Post by Bird on a Fire » Wed Mar 18, 2020 11:12 pm

Brazil's fascist moron president Jair Bolsonaro demonstrates how to wear a mask, demonstrating his customary expertise, dexterity and lightness of touch.

https://i.imgur.com/pidq0cS.mp4
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Re: Exactly why are surgical masks not useful?

Post by dyqik » Thu Mar 19, 2020 12:16 am

Bird on a Fire wrote:
Wed Mar 18, 2020 11:12 pm
Brazil's fascist moron president Jair Bolsonaro demonstrates how to wear a mask, demonstrating his customary expertise, dexterity and lightness of touch.

https://i.imgur.com/pidq0cS.mp4
I think the cover of The New Yorker of Trump with the mask over his eyes had it about right.

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Re: Exactly why are surgical masks not useful?

Post by rockdoctor » Sat Mar 21, 2020 12:18 pm

It occurred to me that the main value of a mask for the average person was as a physical reminder not to touch the mouth. In which case, a scarf over the lower face is just as useful

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Re: Exactly why are surgical masks not useful?

Post by Herainestold » Sat Mar 21, 2020 3:40 pm

Short video from SCMP demonstrating how to fit a surgical mask.

https://www.facebook.com/scmp/videos/2497090587223895/

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