I hate to say "I told you so" but the fact is that masks do nothing to stop the spread of Covid

[nightsafari]

There is a name for it, some kind of a bias. You look for the 'correct' findings to prove you are right.

confirmation bias is the phrase you're looking for.

 

[Leongsam]

 

[Leongsam]

 

[nightsafari]

the non-medical professionals will swarm to it.

 

[Leongsam]

 

[Leongsam]

 

[Leongsam]

sebastianrushworth.com

Covid-19: New evidence on face masks - Sebastian Rushworth M.D.
Author: Sebastian Rushworth, M.D.

8-11 minutes


A few months back I wrote an article about the state of the evidence on face masks. At that point, there were no good studies looking at the effectiveness of face masks in preventing the spread of covid-19 specifically, but there was a systematic review that looked at all randomized trials that had been done on face masks for the prevention of respiratory infections more generally. That review found that surgical face masks reduced the probability of getting a respiratory infection by around 4% in absolute terms (17% in relative terms).
My conclusion was that, considering how infectious covid is, face masks were unlikely to have an effect on the spread of the virus on a population level, although I thought it made sense to use them in hospitals and nursing homes, where you want to do everything possible to minimize the risk of spread to people who are at high risk of a severe outcome.
Now we finally have a randomized controlled trial that has looked at the ability of face masks to protect wearers against covid-19. It was published in the Annals of Internal Medicine. The study was carried out in Denmark, and was funded by a charitable foundation that is connected with a company that owns supermarkets (I’m not sure whether that means they wanted the study to be a success or a failure, or just wanted to know the truth).
In order to be included in the study, participants had to be over the age of 18 and and they had to spend at least three hours per day outside the home. People were not allowed to take part in the study if they had current or prior symptoms that could indicate covid-19 infection, or a previously confirmed diagnos of covid-19. All potential participants had an antibody test performed at the beginning of the study, and if it was positive, then they were excluded from taking part. Participants were recruited through adverts in media and through direct contact with companies and other organizations.
In total 6,024 people were recruited in to the study, and of these 4,862 (81%) followed through to the end. That is a nice big number, which should be able to detect a meaningful difference, if there is one. The average age of the participants was 47 years. Half the participants were randomized to wear a face masks at all times when outside the home, and half were randomized not to. For obvious reasons, this study was unblinded, since it’s hard to create a situation where people are unaware of whether they’re wearing masks or not.
Participants in the intervention group were given 50 disposable surgical masks. This actually increases the probability of the study showing a meaningful effect compared with the reality in most countries where masks are currently being used in public. Why?
Because in most real world situations, people are wearing (and repeatedly re-wearing) non-disposable cloth masks, which are likely much less effective than disposable surgical masks that are only used once. In the systematic review I wrote about in my previous article, the little data there was on cloth masks suggested that they were completely ineffective.
Participants were followed for one month, and at the end of the month an antibody test and a PCR test for covid were carried out. If participants had symptoms suggestive of covid at any point during the month, a PCR test was also performed at that time point. All participants received written and video instructions on how to use the face masks properly. If outside the home for more than eight hours at a time, they were instructed to change to a new mask, so that a single mask was never used for longer than eight hours.
Both an intention-to-treat and a per-protocol analysis was done of the results. What that means is that they looked at what the results were, both if all participants involved in the study were included (intention-to-treat), and if only participants who reported wearing the masks as instructed a high proportion of the time were included in the analysis (per-protocol).
In general, it is considered good form to do an intention-to-treat analysis, and bad form to do a per-protocol analysis. The reason for this is that a per-protocol analysis will tend to make the results seem better than they are in the real world (in the real world, not everyone does as they’re told – annoying, right?!). In this case, however, I think it’s reasonable to also do a per-protocol analysis, because we want to know what effect, if any, masks have when used as instructed.
So, what were the results?
We’ll start with the intention-to-treat analysis. In the face mask group, 1,8% developed covid-19 over the course of the study. In the control group, 2,1% developed covid-19. That is a 0,3% difference in favor of face masks, but it is not even close to being statistically significant.
Ok, let’s look instead at the per-protocol analysis, which in practice means that the 7% of participants who often didn’t follow the mask wearing instructions properly are excluded from the analysis. In the face mask group, 1,8% developed covid-19, and in the control group, 2,1% developed covid-19. So, interestingly, the result was the same regardless of whether you look only at those who wore the masks as intended, or look at everyone, including those who didn’t follow the instructions. This in itself suggests that mask wearing doesn’t make a big difference, since the results don’t change when you only look at people who have been good at wearing their masks as intended.
As an interesting aside, the researchers didn’t just look at covid, they also looked at 11 other respiratory viruses. In the face mask group, 0,5% tested positive for one or more other respiratory viruses. In the control group, 0,6% tested positive. That is a 0,1% difference, and again, it was nowhere close to being statistically significant.
What can we conclude from this?
Wearing face masks when out in public does not meaningfully decrease the probability that the mask wearer will get covid-19. It’s possible that there is a small reduction in risk, but if there is, it is so small that it was undetectable in a study where almost 5,000 people were followed for a month.
It is worth nothing here that the effect seen in studies is usually better than the effect seen in reality. The reason for this is that study participants usually try harder than people who aren’t part of a study, and they get better instruction. In this case, they also had better masks than most people are using at present in reality, and changed to new masks on a regular basis. So, if no meaningful difference was seen in this study, then I think it’s safe to say that no meaningful difference exists in reality.
One thing that is good about this study is that it is the first randomized controlled trial that comes close to mimicking the present reality in many countries, where people are wearing face masks in public, but not at home.
One interesting result of the study was that 52 people in the face mask group and 39 people in the control group reported another individual in the home having covid-19 during the course of the study. Yet of those, only 3 actually developed covid. People sharing a home with someone with covid were really no more likely to get covid than people who weren’t. This suggests that most covid infections happen outside the home, and is in itself something that would be an interesting avenue for further research. It also suggests that most people with covid are not themselves very infectious, giving support to the hypothesis that most infections happen through a small group of highly infectious ”super spreaders”.
The main thing lacking with this study is that it only looked at risk to the person wearing the face mask. It says nothing about the risk that the person wearing the mask will infect another person. That is an equally important parameter, and at present there are no high quality studies looking in to it, so before we can truly say that masks fill no function, we need another large randomized controlled trial that looks at the ability of face masks to prevent the mask wearer infecting other people.
You might also be interested in my article about whether fever lowering drugs are a good idea when you’re sick, or my article about how accurate the covid tests are.
I am a practicing physician in Stockholm, Sweden. I studied medicine at Karolinska Institutet (home of the Nobel prize in medicine). My main interests are evidence based medicine, medical ethics, and medical history. Every day I get asked questions by my patients about health, diet, exercise, supplements, and medications. The purpose of this blog is to try to understand what the science says and to translate the science in to a format that non-scientists can understand. View all posts by Sebastian Rushworth, M.D.

 

[nayr69sg]

These charts don't necessarily tell the whole picture.

Isnt it possible that people got tired of wearing masks? And that mask fatigue has caused the 2nd wave?

 

[nayr69sg]

sebastianrushworth.com

Covid-19: New evidence on face masks - Sebastian Rushworth M.D.
Author: Sebastian Rushworth, M.D.

8-11 minutes


A few months back I wrote an article about the state of the evidence on face masks. At that point, there were no good studies looking at the effectiveness of face masks in preventing the spread of covid-19 specifically, but there was a systematic review that looked at all randomized trials that had been done on face masks for the prevention of respiratory infections more generally. That review found that surgical face masks reduced the probability of getting a respiratory infection by around 4% in absolute terms (17% in relative terms).
My conclusion was that, considering how infectious covid is, face masks were unlikely to have an effect on the spread of the virus on a population level, although I thought it made sense to use them in hospitals and nursing homes, where you want to do everything possible to minimize the risk of spread to people who are at high risk of a severe outcome.
Now we finally have a randomized controlled trial that has looked at the ability of face masks to protect wearers against covid-19. It was published in the Annals of Internal Medicine. The study was carried out in Denmark, and was funded by a charitable foundation that is connected with a company that owns supermarkets (I’m not sure whether that means they wanted the study to be a success or a failure, or just wanted to know the truth).
In order to be included in the study, participants had to be over the age of 18 and and they had to spend at least three hours per day outside the home. People were not allowed to take part in the study if they had current or prior symptoms that could indicate covid-19 infection, or a previously confirmed diagnos of covid-19. All potential participants had an antibody test performed at the beginning of the study, and if it was positive, then they were excluded from taking part. Participants were recruited through adverts in media and through direct contact with companies and other organizations.
In total 6,024 people were recruited in to the study, and of these 4,862 (81%) followed through to the end. That is a nice big number, which should be able to detect a meaningful difference, if there is one. The average age of the participants was 47 years. Half the participants were randomized to wear a face masks at all times when outside the home, and half were randomized not to. For obvious reasons, this study was unblinded, since it’s hard to create a situation where people are unaware of whether they’re wearing masks or not.
Participants in the intervention group were given 50 disposable surgical masks. This actually increases the probability of the study showing a meaningful effect compared with the reality in most countries where masks are currently being used in public. Why?
Because in most real world situations, people are wearing (and repeatedly re-wearing) non-disposable cloth masks, which are likely much less effective than disposable surgical masks that are only used once. In the systematic review I wrote about in my previous article, the little data there was on cloth masks suggested that they were completely ineffective.
Participants were followed for one month, and at the end of the month an antibody test and a PCR test for covid were carried out. If participants had symptoms suggestive of covid at any point during the month, a PCR test was also performed at that time point. All participants received written and video instructions on how to use the face masks properly. If outside the home for more than eight hours at a time, they were instructed to change to a new mask, so that a single mask was never used for longer than eight hours.
Both an intention-to-treat and a per-protocol analysis was done of the results. What that means is that they looked at what the results were, both if all participants involved in the study were included (intention-to-treat), and if only participants who reported wearing the masks as instructed a high proportion of the time were included in the analysis (per-protocol).
In general, it is considered good form to do an intention-to-treat analysis, and bad form to do a per-protocol analysis. The reason for this is that a per-protocol analysis will tend to make the results seem better than they are in the real world (in the real world, not everyone does as they’re told – annoying, right?!). In this case, however, I think it’s reasonable to also do a per-protocol analysis, because we want to know what effect, if any, masks have when used as instructed.
So, what were the results?
We’ll start with the intention-to-treat analysis. In the face mask group, 1,8% developed covid-19 over the course of the study. In the control group, 2,1% developed covid-19. That is a 0,3% difference in favor of face masks, but it is not even close to being statistically significant.
Ok, let’s look instead at the per-protocol analysis, which in practice means that the 7% of participants who often didn’t follow the mask wearing instructions properly are excluded from the analysis. In the face mask group, 1,8% developed covid-19, and in the control group, 2,1% developed covid-19. So, interestingly, the result was the same regardless of whether you look only at those who wore the masks as intended, or look at everyone, including those who didn’t follow the instructions. This in itself suggests that mask wearing doesn’t make a big difference, since the results don’t change when you only look at people who have been good at wearing their masks as intended.
As an interesting aside, the researchers didn’t just look at covid, they also looked at 11 other respiratory viruses. In the face mask group, 0,5% tested positive for one or more other respiratory viruses. In the control group, 0,6% tested positive. That is a 0,1% difference, and again, it was nowhere close to being statistically significant.
What can we conclude from this?
Wearing face masks when out in public does not meaningfully decrease the probability that the mask wearer will get covid-19. It’s possible that there is a small reduction in risk, but if there is, it is so small that it was undetectable in a study where almost 5,000 people were followed for a month.
It is worth nothing here that the effect seen in studies is usually better than the effect seen in reality. The reason for this is that study participants usually try harder than people who aren’t part of a study, and they get better instruction. In this case, they also had better masks than most people are using at present in reality, and changed to new masks on a regular basis. So, if no meaningful difference was seen in this study, then I think it’s safe to say that no meaningful difference exists in reality.
One thing that is good about this study is that it is the first randomized controlled trial that comes close to mimicking the present reality in many countries, where people are wearing face masks in public, but not at home.
One interesting result of the study was that 52 people in the face mask group and 39 people in the control group reported another individual in the home having covid-19 during the course of the study. Yet of those, only 3 actually developed covid. People sharing a home with someone with covid were really no more likely to get covid than people who weren’t. This suggests that most covid infections happen outside the home, and is in itself something that would be an interesting avenue for further research. It also suggests that most people with covid are not themselves very infectious, giving support to the hypothesis that most infections happen through a small group of highly infectious ”super spreaders”.
The main thing lacking with this study is that it only looked at risk to the person wearing the face mask. It says nothing about the risk that the person wearing the mask will infect another person. That is an equally important parameter, and at present there are no high quality studies looking in to it, so before we can truly say that masks fill no function, we need another large randomized controlled trial that looks at the ability of face masks to prevent the mask wearer infecting other people.
You might also be interested in my article about whether fever lowering drugs are a good idea when you’re sick, or my article about how accurate the covid tests are.
I am a practicing physician in Stockholm, Sweden. I studied medicine at Karolinska Institutet (home of the Nobel prize in medicine). My main interests are evidence based medicine, medical ethics, and medical history. Every day I get asked questions by my patients about health, diet, exercise, supplements, and medications. The purpose of this blog is to try to understand what the science says and to translate the science in to a format that non-scientists can understand. View all posts by Sebastian Rushworth, M.D.

Hmm interesting bit about the rate of infection when having a family member covid positive.

Super spreaders. Wont be surprised. However targeting individuals and labeling them is not politically acceptable and against the left wing media principles. So no one will dare do any research suggesting so.

It is all very political now. There is no proper non biased factual research.

One of the things I dont see is the media reporting how many family members catch covid from a child who catches it from school.

Why? Is he number low or high? I suspect it is high. But the politicians want to keep schools open.

However that study suggests otherwise.

Either way what are the actual numbers?

Sigh.

 

[sweetiepie]

More data from Europe that shows mask mandates having no effect whatsoever on the number of cases per million population. If anything they seem to make things worse.

View attachment 96456

KNN my uncle think it's time to close the leescussion on mandate of mask by the below quotes and to add 1 last statement
- it should be worn wiselee and responsibly KNN why wiselee is becas you don't have to mandate wearing it when you are alone in the open and responsibly put it back when you are back to the crowd KNN

After all the noise on both sides of the mask argument re covid-19...generally I think masks don't protect the wearer from getting the virus but it does protect healthy people from getting infected from someone with the virus who wears a mask...so everyone wearing masks does indeed help, save for those who have proven immunity...no doubt wearing a mask is inconvenient but a small price to pay to help the community at large..

KNN my uncle also think this is the correct conclusion KNN but the problem is people will start to think since everyone is wearing then I am safe not wearing KNN

 

[sweetiepie]

KNN my uncle think it's time to close the leescussion on mandate of mask by the below quotes and to add 1 last statement
- it should be worn wiselee and responsibly KNN why wiselee is becas you don't have to mandate wearing it when you are alone in the open and responsibly put it back when you are back to the crowd KNN

Do not wear for the sake of wearing and this stoopid mandatory definitely will lead back to the same leescussion KNN eg
1. Run don't need walk then need KNN then I run and stop run and stop etc what difference does it make ? KNN
2. I don't need to wear while eating in coffeeshop then after eating I walk home without anyone but need to wear wtf is this ? KNN
Bottomline mask does protect others from getting the virus from you but wear it responsibly and wiselee KNN this is not a 1 rule fits all subject KNN

 

[Leongsam]

confirmation bias is the phrase you're looking for.

I was trying to look for data to show that masks work but I could not find any. There were plenty of illustrations, simulations, theoretical scenarios etc but no actual data.

 

[face the facts]

can forsee, next world war.......people with masks against people with no masks

place your bets

 

[mojito]

I think there is going to be a problem with take up of the vaccine.

Nobody wants to be the first ones to get it.

Ask around my doctor friends classmates and colleagues all say if you can try to wait for a while.

So......

Who's going to be first?

Give it to the poor and make govt pay for it.

 

[sweetiepie]

I was trying to look for data to show that masks work but I could not find any. There were plenty of illustrations, simulations, theoretical scenarios etc but no actual data.

KNN my uncle think the only valuable data is to findout the risk of wearing it to protect others leesulting in the increased risk of the wearer themselves KNN only comparing this 2 data then can have a final leecision whether should wear or not KNN

 

[Leongsam]

 

[nightsafari]

I was trying to look for data to show that masks work but I could not find any. There were plenty of illustrations, simulations, theoretical scenarios etc but no actual data.

just filling him in on the word he was looking for.

As for myself, I'm firmly on the fence until there is solid science. A lot of speculation has gone on without any good science. Even your graphs inferencing mask use correlating with covid cases is quite prone to corruption. For eg, could mask use have been disregarded? Were situations where mask use was needed, but not actually mandated? There is too much that's floating around without being nailed down.

Your article from El Pais was good in that it was the first time I saw any data about fomites. Other than that, all we seem to know is symptoms. I've seen no mode of transmission science other than your provided article. For what it's worth, I'm well aware of the uselessness of masks concerning aerosolized pathogens. There's a reason why infectious agent lab workers used closed environment suits and not surgical masks.

I sense instead you're pretty upset about being stuck in a herd of sheeple who overly dictate your movements....

Oh and I'm going to rub it in a little. How are you loving the landslide your dear Ardern got?

 

[Leongsam]

just filling him in on the word he was looking for.

As for myself, I'm firmly on the fence until there is solid science. A lot of speculation has gone on without any good science. Even your graphs inferencing mask use correlating with covid cases is quite prone to corruption. For eg, could mask use have been disregarded? Were situations where mask use was needed, but not actually mandated? There is too much that's floating around without being nailed down.

Your article from El Pais was good in that it was the first time I saw any data about fomites. Other than that, all we seem to know is symptoms. I've seen no mode of transmission science other than your provided article. For what it's worth, I'm well aware of the uselessness of masks concerning aerosolized pathogens. There's a reason why infectious agent lab workers used closed environment suits and not surgical masks.

I sense instead you're pretty upset about being stuck in a herd of sheeple who overly dictate your movements....

Oh and I'm going to rub it in a little. How are you loving the landslide your dear Ardern got?

I like Arden she's a nice person. She deserves to win just as National deserves to lose for imploding 6 months out from the election. What I do not like is the influence of the Green party on labor policies and it is for that reason that lots of centre right voters abandoned National and voted labor just to keep the greens out and that includes yours truly.

However for the long term good of the country someone other than Arden needs to take the reigns. Touchy feely policies can only get you so far.

 

[face the facts]

just filling him in on the word he was looking for.

As for myself, I'm firmly on the fence until there is solid science. A lot of speculation has gone on without any good science. Even your graphs inferencing mask use correlating with covid cases is quite prone to corruption. For eg, could mask use have been disregarded? Were situations where mask use was needed, but not actually mandated? There is too much that's floating around without being nailed down.

Your article from El Pais was good in that it was the first time I saw any data about fomites. Other than that, all we seem to know is symptoms. I've seen no mode of transmission science other than your provided article. For what it's worth, I'm well aware of the uselessness of masks concerning aerosolized pathogens. There's a reason why infectious agent lab workers used closed environment suits and not surgical masks.

I sense instead you're pretty upset about being stuck in a herd of sheeple who overly dictate your movements....

Oh and I'm going to rub it in a little. How are you loving the landslide your dear Ardern got?

best solution is.....those who love wearing masks, by all means go ahead, wear double layer or triple if u like
just dont force others to wear....fair? knn

 

[tobelightlight]

Do you REALLY understand how "masks" work?

"Somebody recently said they didn't understand how masks worked.

So I told them: The way masks "work" is they trap bacteria, spit and moisture in a small space for you to breath it back in. Over and over.

Your body breathes that stuff OUT for a reason.

The lungs are a MAJOR way that our bodies EXPELL "bad" things we don't want. Keeping it breeding, moist, warm, and flooding back again into our lungs will MASSIVELY increase lung infections, flu and other illnesses this year, and "they" know this.

This is WHY they want us to wear the masks. Then, they get to count all of the illnesses and deaths as "covid" and scare the hell out of all of the blind fools - which will, among other things, get more people wearing masks more of the time.

Did you know that the VAST majority of "cases" are people who have been obediently wearing masks the entire time? The evidence is undeniable. (For those who will look.)
See, it's a lot like taking a shit and then stuffing it back down your throat. Taking what your brilliant body wisely put out and then stupidly, stubbornly (and obediantly) stuffing it back in.

And all to prevent a virus that might not actually be killing anyone.

Now do you understand how masks work?

It's True."

~ Brian D Ridgeway