Danish study shows no significant reduction of Covid-19 in wearers of surgical masks

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MountainDude said:
Just because someone has an MD/PhD does not mean they are smart and does not mean they don't have a political agenda. I am not sure which case this is, but his thread title "Danish study shows no significant reduction of Covid-19 in wearers of surgical masks" is taken out of the context of the original quoted research and is spreading FALSE information.
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maybe you didn't look hard enough at the image I posted.
 
eman1200 said:
maybe you didn't look hard enough at the image I posted.
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I did not! Pretty funny, but unfortunately I take this thread seriously. This kind of spread of false information from doctors and scientists is why 2000 Americans will die TODAY.
 
wayne said:
I wish I had the rules my Dad had working at TVA. Their sick days just accumulated. Ours roll off at the end of the year, and we can only use them for sick days (including taking care of family), no using them for extra vacation time. I rarely take a sick day. With sick people staying at home and the ability to work from home if I don't feel well I almost never use a sick day. In 15+ years at my current employer I would have had months of sick day accrued and one BIG check when I retire.
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I got told when I hired into the government to not use your sick time if you can avoid it. Always use your annual leave or other types of leave as sick has unlimited accrual. This can give you years worth of time at your retirement.
 
MountainDude said:
I did not! Pretty funny, but unfortunately I take this thread seriously. This kind of spread of false information from doctors and scientists is why 2000 Americans will die TODAY.
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And of those, how many were absolutely 100% healthy with no comorbidity conditions? I mean, if we are just gonna throw out numbers, lets just toss out that the CDC revised the 200,000 deaths - to say that only something like 30k didn't have comorbidity conditions. So - car accident numbers.
 
Katamarino said:
DK37nuH.jpg
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So... this image is posted in response to a thread created by a multi-degreed, extremely well-read and literate authority, whether or not you agree with his interpretations? That says quite a bit about ... well... lots of things. Perhaps if the above image were captioned, "If the Black Plague happened in 2020, Politicians: Do what we tell you ... People in the US: Umm.. That's not why we built this country".... of course, the image would have to be changed 'cause licking rats wouldn't make sense... not that it does now, or that it's an even remotely accurate representation of ANY attitude present today that I'm aware of.
 
MountainDude said:
Do we need a scientific consensus that a mask that covers the mouth and nose slows down the spread of a RESPIRATORY virus?
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Masks are not created equal.
 
One thing is certain, the mask mandates have greatly expanded a stream of pollution.
 
bnt83 said:
One thing is certain, the mask mandates have greatly expanded a stream of pollution.
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Well, so has the rapid increase in home delivery of food/goods. Lots of plastic/Styrofoam/cardboard packaging being tossed in the garbage every day since bulk quantities aren't being sold in as great a quantity. Gloves/masks/etc. are already ending up in waterways in large amounts.
 
So I decided to sit down and parse out further why some posters here would think the original title on this thread was misleading. Many of you may not be interested in such fine linguistic parsing, so may not want to read the rest of this. But I hope it might shed some light on the subject. And I hope my interest in this is understandable given that I am the son of a linguist (a complete aside, but it still brings a smile to me to think of how my late father delighted in asking young children what the 3 or more meanings of the sentence "I saw a man eating shark" are :)

So the original title of this thread was "Danish study shows no significant reduction in Covid-19 with surgical mask wearing". I think whether this is misleading can be better understood by substituting some more neutral details about what the claim that the study said is. Consider the following possible titles, both of which are literally true statements about the study by Bundgaard et al:

1. Danish study shows no significant reduction in headaches with aspirin use.

2. Danish study shows no significant reduction in earthquakes with peanut butter consumption.

#1 makes a true statement, the study has nothing to do with headaches or aspirin us and so shows no reduction in same. At the same time, it is well established that aspirin use does decrease headaches. So someone reading #1 might assume that the author was trying to imply that the statement that aspirin use reduces headaches is false, even though that is not what was literally said.

#2 also makes a true statement, the study has nothing to do with earthquakes or peanut butter consumption. Since this latter assertion is fairly clearly false, most people would not assume the author of the title was trying to mislead about the contents of the study. They might think it was some kind of headline from Mad magazine.

In the case of the actual original title, the whole point here is that the evidence for the claim that masks prevent the spread of Covid-19 is not terribly convincing. It is likely best described as mixed prior to this paper. So from that perspective, there is no attempt to mislead at all. Rather the title makes a true statement which points to an important set of considerations about the evidence.

If one assumes it is well established that mask wearing by the general public slows the spread of Covid-19, then one might be inclined to make the assumption that the title is somehow misleading, as per example #1. But that is an assumption and then begs the real underlying question about the strength of the evidence for the efficacy of such mask wearing.

As to the 2nd and current title, I think it is correct and much less subject to such misinterpretation. The study says that there was no significant effect of reducing infections in those wearing surgical masks.
 
MountainDude said:
You are trying to make people believe that masks do not do anything under all circumstances, which is FALSE.
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As to this assertion that I am trying to "make people believe that masks do not do anything under all circumstances" -- I am sorry that is a complete straw-man and I never stated that. To expand a bit on the actual evidence regarding the efficacy of mask wearing in preventing people from being infected by Covid-19:

The results of the WHO metaanalysis are fairly clear that healthcare workers wearing N95s are about 95% less likely to become infected. It also reported that healthcare workers wearing 12-16 layer cloth masks may have had an 78% reduction (though these were in Chinese and not presently available online).

But these results are a far cry from the situation with the general public wearing cloth masks, where the evidence is much more mixed because there are a lot of other factors in play. Please do critically read the reviews posted on my medical interest page at http://steinmetz.org/peter/Medical/. I think you will see the evidence was fairly evenly divided - prior to this recent study. If after doing so, you want to parse in detail the meaning of the studies underlying those reviews, I am happy to do so. There is evidence on both sides, though I think with this more recent study it weighs toward mask mandates not being advisable.
 
Peter,

Most people can accept the fact that there's little scientific data showing that wearing a typical cloth or disposable mask protects the wearer, and the studies you cited in this thread support that. Can you address the efficacy of masks in terms of preventing the spread of Covid FROM the wearer to the people with whom they have contact inside of social distancing guidelines (or should I say "outside of social distancing guidelines?" ... your linguistic background has me all paranoid now..... grin... )? That seems to be the source of antipathy towards your original post.

Thanks for your thoughts.
 
PeterNSteinmetz said:
As to this assertion that I am trying to "make people believe that masks do not do anything under all circumstances" -- I am sorry that is a complete straw-man and I never stated that.
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You stated that this study provided evidence that mask mandates are unwise:

PeterNSteinmetz said:
With this study, I think the evidence now weighs on the side of NOT wise.
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Using this study to support your conclusion that mandatory mask wearing is unwise, again, is a perversion of logic and an irrational extrapolation of the data.

"Thus, these findings do not provide data on the effectiveness of widespread mask wearing in the community in reducing SARS-CoV-2 infections."​
 
PeterNSteinmetz said:
... I think with this more recent study it weighs toward mask mandates not being advisable.
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Not being advisable or just not necessarily being effective? IOW are masks actually said to be pernicious? (No, I'm too lazy to read the studies.)
 
PeterNSteinmetz said:
I think it is rather unfair to try and characterize the original title as "horribly misleading" and then support that assertion by quoting a phrase out of context and chopping off the transitional "Thus," which indicated that more context was required.
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I didn't take the statement out of context. The researchers did not study the effect of masks on community spread. Period. No context is needed to understand that statement.
 
dmspilot said:
You stated that this study provided evidence that mask mandates are unwise:



Using this study to support your conclusion that mandatory mask wearing is unwise, again, is a perversion of logic and an irrational extrapolation of the data.

"Thus, these findings do not provide data on the effectiveness of widespread mask wearing in the community in reducing SARS-CoV-2 infections."​
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I disagree. Please see my response to MuseChaser’s query.
 
So I flipped a coin once and it landed on heads.
PeterNSteinmetz's conclusion: It must be a two-headed coin.
 
MuseChaser said:
Peter,

Most people can accept the fact that there's little scientific data showing that wearing a typical cloth or disposable mask protects the wearer, and the studies you cited in this thread support that. Can you address the efficacy of masks in terms of preventing the spread of Covid FROM the wearer to the people with whom they have contact inside of social distancing guidelines (or should I say "outside of social distancing guidelines?" ... your linguistic background has me all paranoid now..... grin... )? That seems to be the source of antipathy towards your original post.

Thanks for your thoughts.
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Good question and I think goes to the heart of the scientific matter as well as why some posters have misinterpreted the original title to be misleading.

So the question is essentially - is there good scientific evidence to support the use of masks by the general public to prevent others from being infected?

There are no good randomized controlled studies of this at this time. They would be difficult to successfully implement.

There are in-vitro reasons to believe it should work, such as masks decreasing expelled droplets.

There is one observational study, with some serious issues in my opinion, on the effect of mask mandates on Covid-19 case rates. It showed a small effect in decreasing cases rates.

There are the international studies, which are really subject to a lot of cautions in interpretation.

The rest of the data is less direct. For example, there is data that when you put a mask mandate in place, people spend more time outside the home, often in risky areas.

Put all of this together, as the scientific reviews listed on my page attempt to do, and you end up with a pretty mixed set of evidence, about 50/50.

As to the meaning of the Bundgaard study. I do not think it is completely irrelevant to this question, though did not directly address it, as noted by the authors.

Here is why. For the results of Bundgaard et al to be true and for there simultaneously to be a strong source control effect of mask wearing would require the masks to someone have an asymmetric effect. But we know that the likelihood of people being infected is related to the total number of virions they are inhaling or ingesting. And there is no evidence that the masks are somehow rectifiers, blocking virions in only one direction.

So how could that be one way? Just imagine two people in a room, one infected and the other not. Why would it matter who wore the mask?

This seems physically improbable to me so I think that indirectly implies that if Bundgaard’s results are true, they argue against the source control effect. That is indirect evidence, but I certainly don’t think that Bundgaard’s results argue FOR source control.

In terms of whether mask mandates are wise, this involves a variety of other political and sociological considerations, but again, I don’t think the Bundgaard results can be said to argue IN FAVOR of mask mandates. Rather they add to a growing set of evidence to think they are unwise.
 
dmspilot said:
So I flipped a coin once and it landed on heads.
PeterNSteinmetz's conclusion: It must be a two-headed coin.
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I don’t know I would draw that conclusion. But I would say that it is far more likely to be a two-headed coin than a two-tailed one and the probability of it being two-headed, assuming some reasonable prior probabilities of it being two-sided, two-tailed, or fair, just went up!
 
Where’s the study that shows how 7200 exhales per person per day just disappear into the ether?
 
PeterNSteinmetz said:
...

So how could that be one way? Just imagine two people in a room, one infected and the other not. Why would it matter who wore the mask?

...
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Thanks for the reply, Peter. As a complete layperson, I'd postulate the answer to that question may lie in the amount of space the virus would have to travel from the person expelling the virus to the mask. If the infected person was wearing the mask, the virus' ability to bridge the distance to the uninfected non-mask-wearing person would be strongly compromised by the mask, no? Conversely, if the infected person was NOT wearing the mask, the virus would have a much greater chance of reaching the non-infected person, and bypassing the little-to-no protection that mask offers to the wearer in terms of self-protection, since the virus could land anywhere on that person and be transmitted internally by habitual, unintentional hand-to-eye, -nose, or -mouth contact, on top of the possibility of being drawn through the mask via inhalation. Does that make sense?
 
The Management Council understands that subject matter like this, has the potential to delve into the political realm. We will choose to leave it open, as long as everyone can behave and stay out of the spin zone.
 
MuseChaser said:
Thanks for the reply, Peter. As a complete layperson, I'd postulate the answer to that question may lie in the amount of space the virus would have to travel from the person expelling the virus to the mask. If the infected person was wearing the mask, the virus' ability to bridge the distance to the uninfected non-mask-wearing person would be strongly compromised by the mask, no? Conversely, if the infected person was NOT wearing the mask, the virus would have a much greater chance of reaching the non-infected person, and bypassing the little-to-no protection that mask offers to the wearer in terms of self-protection, since the virus could land anywhere on that person and be transmitted internally by habitual, unintentional hand-to-eye, -nose, or -mouth contact, on top of the possibility of being drawn through the mask via inhalation. Does that make sense?
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Exactly. I don't know how someone so educated can't see a difference between coughing into a mask 1 cm from your mouth and having your cough unrestricted and expelling moisture into an open room. It's obvious that surgical masks have gaps than, when you inhale, air will leak from all around the border allowing you to take in whatever particles are floating around.
 
MuseChaser said:
Thanks for the reply, Peter. As a complete layperson, I'd postulate the answer to that question may lie in the amount of space the virus would have to travel from the person expelling the virus to the mask. If the infected person was wearing the mask, the virus' ability to bridge the distance to the uninfected non-mask-wearing person would be strongly compromised by the mask, no? Conversely, if the infected person was NOT wearing the mask, the virus would have a much greater chance of reaching the non-infected person, and bypassing the little-to-no protection that mask offers to the wearer in terms of self-protection, since the virus could land anywhere on that person and be transmitted internally by habitual, unintentional hand-to-eye, -nose, or -mouth contact, on top of the possibility of being drawn through the mask via inhalation. Does that make sense?
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I think that would operate on the assumption that the typical mask does any meaningful filtering of the virons, correct? If you stand behind a screen door and I spray it with a garden hose, you're still going to get soaked. I would presume that unless the masks worn by the infected source are of sufficient filtering media to truly "catch" the virons or the majority of them, it's leaking like the proverbial sieve.
 
Peter, not only are you spreading false information, you are defending your actions.
Since science does not work for you, here is a metaphor:
Let's say a person named "Joe" is given a drug, as part of a trial.
Under this drug, Joe is given an intelligence test and his score is "imbecile".
Do you think Joe would like to see a report that says "Joe is an imbecile", without the context?
Maybe now you get it?
 
SoonerAviator said:
I think that would operate on the assumption that the typical mask does any meaningful filtering of the virons, correct? If you stand behind a screen door and I spray it with a garden hose, you're still going to get soaked. I would presume that unless the masks worn by the infected source are of sufficient filtering media to truly "catch" the virons or the majority of them, it's leaking like the proverbial sieve.
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The idea is that the mask takes the velocity out of the air, or at least redirects the stream away from the person you're talking to, thus reducing the chance of virons reaching them.
 
MountainDude said:
Peter, not only are you spreading false information, you are defending your actions.
Since science does not work for you, here is a metaphor:
Let's say a person named "Joe" is given a drug, as part of a trial.
Under this drug, Joe is given an intelligence test and his score is "imbecile".
Do you think Joe would like to see a report that says "Joe is an imbecile", without the context?
Maybe now you get it?
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Sorry that metaphor is inaccurate. You keep repeating that I am spreading false information. Please quote the false statements and cite to studies showing they are false or stop simply repeating your assertion. That is also a fallacy.
 
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