Study finds mask wearing cuts covid incidents by 53%

[greentea5]

According to researchers at Monash University and the University of Edinburgh, writing in the BMJ:

"Results from more than 30 studies from around the world were analysed in detail, showing a statistically significant 53% reduction in the incidence of Covid with mask wearing and a 25% reduction with physical distancing.

Handwashing also indicated a substantial 53% reduction in Covid incidence, although this was not statistically significant after adjusting for the small number of handwashing studies included.

Detailed analysis was not possible for other measures, including quarantine and isolation, universal lockdowns, and closures of borders, schools, and workplaces, due to differences in study design, outcome measures and quality, the researchers said..."

You can read more at the Guardian. Sadly in England mask wearing continues to be low, I'd estimate about 10% are wearing masks on the buses where I am.

There are also some real world studies:
"...Another study in China found that, in 124 households where there had been a laboratory-confirmed coronavirus case, mask wearing by both the patient and the other inhabitants reduced transmission within the household by 79%.

Aboard the USS Theodore Roosevelt, where living quarters and working environments leave little room for social distancing, a study found there was a 70% reduced risk of infection among those who used a face covering.

In Thailand, a retrospective case-control study found that among 1,000 people interviewed as part of contact tracing investigations, those who reported always having worn a mask during high-risk exposures again experienced a 70% reduced risk of becoming infected compared with others.

An international report published in The Lancet, which analysed data from 172 studies in 16 countries, found that by wearing a face mask there is just a 3% chance of catching COVID-19..."

news.sky.com/story/covid-19-what-does-the-science-actually-say-about-face-masks-12349337

And this is the link to the Guardian reporting on the study mentioned in the BMJ: www.theguardian.com/world/2021/nov/17/wearing-masks-single-most-effective-way-to-tackle-covid-study-finds

This is why I still wear a mask. It’s not a silver bullet, but it can help, and can save lives. We have 200 people dying a day at the moment from C19, 1000 people a day being hospitalised.

Its always been a fairly obvious barrier. This study confirms it. I have never understood the resistance.

Hopefully this stops anti maskers saying mask doesn't work.

Yeah but mask wearing protects others not yourself. Why should I wear a mask to protect them when they aren’t wearing a mask to protect me?

@Spedder

Yeah but mask wearing protects others not yourself. Why should I wear a mask to protect them when they aren’t wearing a mask to protect me?

Have you read the OP? One study showed people who always wore a mask during high risk exposure had a 70% reduced risk of becoming infected. Another study showed that wearing a face mask leads to just a 3% chance of catching covid. Plenty of studies showing that wearing a mask protects the user as well as others.

No, the “study” does not say that.

From John Burn-Murdoch:

twitter.com/jburnmurdoch/status/1461325657653317640

The good thing about this story is that any time I see someone sharing it as evidence that wearing masks cuts Covid incidence by 53%, I know they haven’t read the paper it’s based on and aren’t fussed about the quality of evidence as long as it produces the right number 🙃

Plenty of studies showing that wearing a mask protects the user as well as others.
The news and the government have frequently emphasised that masks only protect others not yourself. If a mask can protect yourself too then they’re keeping very quiet about it!

@Spedder

Yeah but mask wearing protects others not yourself. Why should I wear a mask to protect them when they aren’t wearing a mask to protect me?

That’s quite a selfish mindset.

@wintertravel1980

No, the “study” does not say that.

From John Burn-Murdoch:

twitter.com/jburnmurdoch/status/1461325657653317640

The good thing about this story is that any time I see someone sharing it as evidence that wearing masks cuts Covid incidence by 53%, I know they haven’t read the paper it’s based on and aren’t fussed about the quality of evidence as long as it produces the right number 🙃

Out of interest, why are you putting study in quotation masks?

It's a well conducted systematic review and meta-analysis.

53% is the estimate produced from the main analysis, which is why I imagine the guardian quoted it though would've been better if they caveated it which the sensitivity analyses included. When studies at high risk of bias were included, the estimate is reduced, but remains significant.

It was always pretty obvious that as a barrier, it would help.

The nice thing, now it's cold, it keeps my face warm too

A big proportion of mask wearer aren't wearing them correctly and are wearing a face covering that isn't going to do much.

Of course clinical grade ones work and I appreciate medical staff who wear them

@Spedder

Plenty of studies showing that wearing a mask protects the user as well as others. The news and the government have frequently emphasised that masks only protect others not yourself. If a mask can protect yourself too then they’re keeping very quiet about it!

It really depends on what mask you wear and how well it’s fitted. I have masks and my friends and family do that protect the wearer, as opposed to one made of T-shirt material etc. How do you think health care staff cope with their proper masks? They protect the wearer.

Entirely anecdotally, we've found that our school minibuses don't seem to have connected COVID cases...we have assumed that it's due to face covering wearing. This study doesn't surprise me in the least.

@Spedder

Yeah but mask wearing protects others not yourself. Why should I wear a mask to protect them when they aren’t wearing a mask to protect me?

I wear a mask to model considerate behaviour as well as to make it easier for those who feel they have to wear one due to delicate health, or are wavering but feel too self conscious or whatever. Modelling positive behaviour is something our government could do a lot better on, I feel.

A big proportion of mask wearers aren't wearing them correctly and are wearing a face covering that isn't going to do much

It may not do "much" but if it does even a little bit, surely it's better than not wearing one at all?

Mask wearing doesn’t seem to be working in the continent. All these measures just kick the can a little further down the road.

@stairway

Mask wearing doesn’t seem to be working in the continent. All these measures just kick the can a little further down the road.

...and help the government and healthcare see what's happening so they can adjust or introduce other measures to slow the spread where needed? Totally useless, you think?

@stairway

Mask wearing doesn’t seem to be working in the continent. All these measures just kick the can a little further down the road.

Seems to be working very well in the country’s that have mandated continued mask wearing with high vaccination rates (Italy, Spain, Portugal).

Many parts of Germany gave up on masking recently and now look what’s happening there.

@Spedder

Plenty of studies showing that wearing a mask protects the user as well as others. The news and the government have frequently emphasised that masks only protect others not yourself. If a mask can protect yourself too then they’re keeping very quiet about it!

The news and the government have all mentioned that mark wearing can help protect both the wearer and others.

Out of interest, why are you putting study in quotation masks?

It's a well conducted systematic review and meta-analysis.

Meta-analysis of poor quality research produces poor quality conclusions.

Here is the BMJ editorial that outlines some of the shortcomings of the mask effectiveness “study” referenced by the Guardian and Sky.

www.bmj.com/content/375/bmj.n2729

I accept that masks might be 10% effective. This number is in line with earlier estimates produced by the UK SAGE (who quoted a range of 6-15%). Anything higher than 10-15% is not supported by any of the real life data.

@521Jeanie

A big proportion of mask wearers aren't wearing them correctly and are wearing a face covering that isn't going to do much

It may not do "much" but if it does even a little bit, surely it's better than not wearing one at all?

I assume you mean the people who cover their nose and mouth because the people who wear them as chin warmers are not doing anything apart from pissing me off- I'd rather they wear nothing.

If it's a fresh thin mask then it might catch a little but too many are reusing masks without washing in between which can't be good for the wearer.

Anything higher than 10-15% is not supported by any of the real life data.

If this is true, why the country like Japan doing so well? Over populated city with packed subways and busy places, no real lock downs and still the cases are so low.

@wintertravel1980

Out of interest, why are you putting study in quotation masks?

It's a well conducted systematic review and meta-analysis.

Meta-analysis of poor quality research produces poor quality conclusions.

Here is the BMJ editorial that outlines some of the shortcomings of the mask effectiveness “study” referenced by the Guardian and Sky.

www.bmj.com/content/375/bmj.n2729

I accept that masks might be 10% effective. This number is in line with earlier estimates produced by the UK SAGE (who quoted a range of 6-15%). Anything higher than 10-15% is not supported by any of the real life data.

Yup, and a high quality syst review and meta-analysis includes all identified studies, assesses for ROB, and conducts sensitivity analyses to assess impact of bias and calculate various iterations of efficacy

Which is exactly what the authors have done, as I outlined in my post

53% is the estimate produced from the main analysis, which is why I imagine the guardian quoted it though would've been better if they caveated it which the sensitivity analyses included. When studies at high risk of bias were excluded, the estimate is reduced, but remains significant.

FFP2 masks absolutely protect the wearer as well as other people. However, I'm more than happy to wear a mask to protect others; it seems sociopathic to me not to without a very good reason. I just wish more people would return the courtesy.