On August 31st, a new randomised controlled trial on mask efficacy was published online. This study is the first of its kind. While the well-known Danish mask study looked at whether wearing a mask reduces one’s own risk of infection, the new study looked at whether community masking reduces the general level of infection.
The main argument for wearing a mask has always been that it makes infected people less likely to transmit the virus, rather than it provides any protection to the wearer. Hence the new study is a far more valid test of the claim that community masking ‘works’.
As I’ll explain, however, it’s a missed opportunity. And this is a shame because some aspects of the experimental design are quite powerful, and – given the number of people involved – it must have been very expensive (meaning there’s now less money available for the next big study).
The basic set-up was as follows. The authors randomly assigned 600 villages in rural Bangladesh – comprising more than 300,000 people – to one of two groups: an intervention group and a control group.
Villages in the intervention group received an eight-week mask promotion campaign, which involved distribution of masks, promotion of masks in public spaces, and role-modelling by community leaders (including imams at local mosques). Villages in the control group did not receive any interventions.
The main outcome variables were measures of seroprevalence. Using phone and in-person surveys, the researchers obtained data on the number of people who experienced COVID-19 symptoms after the intervention. They then collected blood samples from some of those individuals to gauge the number who were seropositive.
Overall, mask-wearing reached 42.3% in the intervention villages, compared to 13.3% in the control villages. What about the outcome variables? 7.6% of participants in the intervention villages reported COVID-19 symptoms, compared to 8.6% in the control villages.
And when the researchers zoomed in on those who reported COVID-19 symptoms and tested positive for antibodies, the seroprevalence was 0.68% in the intervention villages, versus 0.76% in the control villages. (Note: the figure in the chart below is ‘0.69’ because it’s an adjusted value from a model.)
Among the intervention villages, some had been randomly assigned to get cloth masks, whereas others had been randomly assigned to get surgical masks. The researchers compared these two groups, and found that the reduction in seroprevalence was larger for the surgical mask group. They also found that the reduction was concentrated among individuals aged 50+ (see p.28).
Given that the intervention increased mask-wearing by 29 percentage points, the results suggest that going from 0% to 100% mask-wearing could reduce the seroprevalence of COVID-19 by as much as 36%. (That is, 100/29 x [0.76 – 0.68]/0.76.) And the reduction could be even greater for individuals aged 50 and over.
However, there are several weaknesses of the study, which mean that this interpretation is not necessarily correct, and – in fact – may very well be wrong.
One criticism is that the ‘p-values’ corresponding to the main results are rather high (see chart above). Note: a p-value quantifies the degree of statistical confidence one can have in an ‘effect’ of given magnitude; the smaller the value, the more confidence.
Although two out of the three are below the conventional threshold of 0.05, they are only just below it. This raises questions about the robustness of the results. On the other hand, the p-value corresponding to the difference in seroprevalence among those aged 60+ does appear to be quite low.
However, a much more serious criticism is that the study is not actually a randomised trial of mask-wearing. Rather, it is a randomised trial of mask promotion campaigns. This means that, even if the intervention did have an effect, that effect was not necessarily brought about by more people wearing masks.
A true randomised trial of mask-wearing would have had two groups: each receiving the same promotion campaign, except in one group the masks would have been genuine, and in the other they would have been fake (e.g., made out of a more porous material). For ethical reasons, this kind of study might not be allowed.
As an alternative, the researchers could at least have given each of the two groups a ‘COVID-19 awareness campaign’, and then only distributed masks to the intervention group.
Yet in the study itself, the control villages received no interventions. It’s therefore plausible that seroprevalence ended up being lower in the intervention villages not because of greater mask-wearing, but because the campaign made people more concerned about COVID-19 in general, and hence caused them to change their behaviour in other ways.
For example, they might have become more likely to avoid crowds, to ventilate their homes or to stay at home when sick. As a matter of fact, the researchers also measured physical distancing, and found that this was greater in the intervention villages.
One counter-argument is that the greater efficacy of surgical masks than cloth masks suggests the results really are explained by mask-wearing. (Surgical masks appear to be more effective in lab experiments.) However, this result is also consistent with the alternative explanation.
Given that surgical masks are ordinarily worn by healthcare workers or people dealing with hazardous materials, seeing them every day may have prompted greater concern among participants. And in fact, physical distancing increased by slightly more in the intervention villages that received surgical masks. People in those villages may have also changed their behaviour more in ways that weren’t measured.
Some commentators have argued that it doesn’t matter whether the effect came about through greater mask-wearing or other behavioural changes. What matters, they say, is that the mask promotion campaign reduced seroprevalence.
However, this is not a convincing argument. First, while a mask promotion campaign could plausibly affect people’s behaviour in remote Bangladeshi villages, it would be unlikely to have any such impact in countries like the U.K., where the pandemic is already highly salient.
Second, if it was the campaign that mattered, rather than the mask-wearing itself, the same effect could be achieved far more cheaply in the future. For example, rather than distributing thousands of masks to villagers, one could simply inform them about the risks of COVID-19, as well as the importance of social distancing and ventilation.
The Bangladesh mask study could have resolved the debate over whether community masking ‘works’. Unfortunately, it’s a massive missed opportunity. All it really tells us is that promoting mask-wearing while also making the pandemic more salient leads to a reduction in seroprevalence among older people living in rural Bangladesh.
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sequenced DELTA deaths from 15th August to 29th August
vaccinated unvaccinated
<50 10 27
>50 402 119
all 412 146
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1014926/Technical_Briefing_22_21_09_02.pdf
and
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1012644/Technical_Briefing_21.pdf
At first glance, given that the older groups were jabbed first, it suggests whatever effect the jabs might have don’t last. OR the jabs take a bit of time produce the negative health effects many have predicted.
its all complicated by not knowing who was jabbed. some unvacced older people may have been too ill or too comatose to give permission
some young people may have been vulnerable so jabbed first
can’t really tell without knowing more than the information that they’ve given – which makes me think its not that effective
Indeed
I think you really need to control for underlying state of health, and also whether it was FROM or WITH
Conclusion 1: Masks cause a 1% overall change in reported symptoms and a 0.1% overall change in seroprevalence.
Conclusion 2: Masks could result in a 36% reduction in infections.
No prizes for guessing which of those two will be plastered all over the media, if at all.
Not sure what the point of this news from rural Bangladesh is, to be honest..
Umm… clarification please?
You’ve hit the nail on the head – in the absence of clear criteria concerning the Covid-19 symptoms reported, the study becomes irrelevant, as it is impossible to state with certainty that the researchers were comparing like with like.
Well, there is that, but what I meant is that both of those numbers are referring to “intervention villages”.
Ah, I see – I hadn’t noticed the duplication of the word!
This typo is now fixed.
sure, go ahead and extrapolate a non-significant difference of .07% to the entire population, it will be just as accurate as anything else that’s been done in the past 18 months.
The last 18 months has been a storm of studies of this kind that have almost no value, clarify nothing but are misrepresented, mostly by mainstream media, to push a pre-established narrative.
That’s nothing: there has been 40 years of this sort of confected study over climate change!
The criticisms of the structure of the trial are valid.
However the argument over p values isn’t : the 0.05 isn’t a ‘cut-off’ – it’s an accepted convention about drawing a line on a continuum.
Bottom line : there is still no cumulative or substantive evidence to justify mask-wearing.
And yet masks everywhere despite the complete absence of proof of any health benefit.
Masking and vaxxing, is the new western religion.
Sunk cost fallacy and huge incentives for personal enrichment are going to make these policies continue. In fact, the German vaxx app already contains text to urge people to “make all efforts to renew the certificate” before its expiry date 1 year from now on. With a few hundred million vaccine doses for 2022 already ordered by our wise minister, it is very evident that the pandemic CANNOT end in the next 12 months at the very least. And 12 months from now, the motivation will not change at all, rather, by emboldening the actors the orgy of public money waste is only likely to continue. As we can see, people do not get tired of this scam, but can be milked over and over again, with new “variants” already on the horizon.
I think your analysis is right. The drug pushers are massively invested – politically and financially – in willing a continuing ‘pandemic’ into being.
In fact, there hasn’t even been an epidemic as properly defined.
Just re-read and noticed this:
so not only relying on self-reporting but then only testing some of those people? Absolutely no scope for fudging the results to get the conclusion you want then.
What an absolute waste of time we know masks do fuck all they are just a sign of brain washed compliance of the flock.
Found the link to the preprint of the study. It seems that the monitoring of proper mask wearing was done quite well – observation in public places by observers who were not the intervention team.
However, the results are pretty hard to interpret. There seems to be about a 10% reduction in the risk in the village as a whole – but this tells you almost nothing, for example, about the reduction in risk to others of insisting on wearing masks in your shop.
Well-resourced entity badly wants to sell mandatory facemasks. Tries hard to fabricate evidence they actually do something.
That’s all which needs to be known about this.
Love it or hate it, masks do have the side effect that people like myself avoid at all cost any place which requires wearing masks, especially any place which is supposed to offer leisure or entertainment (I’d rather have no entertainment at all than pretend to be entertained while muzzled). So mask mandates are basically a backdoor self-isolation policy. And that’s how they “work”, even with those who affirm the idiocy of the policy at large.
Incidentally, by the same token threatening witches to be burned at stakes will work wonders to shut them up and become very pious.
The only question is, do we want to have those sort of policies in the modern civilized world, and the resounding answer is NO.
The paper on the Bangladesh mask trial opens:
“Mask usage remains low across many parts of the world during the COVID-19 pandemic, and strategies to increase mask-wearing remain untested. Our objectives were to identify strategies that can persistently increase mask-wearing and assess the impact of increasing mask-wearing on symptomatic SARS-CoV-2 infections.”
The study is led by someone from Yale School of Management aka Deep State technocrat central.
Well, one way of persistenly increasing mask-wearing is to get the CIA-funded death squads to go around executing anyone who doesn’t comply, as done to those opposing neo-liberalism in South and Central America.
Seriously, the study seeks increase persistent wearing of masks irrespective of efficacy in a dirt poor country. This is White Man’s Burden stuff, getting the pesky natives to do what is good for them. That is such a difficult and thankless task. But someone has to do it, proviing the project funding is there.
Here’s a clue, in dirt poor countries people have a choice between buying food or repairing the shoes of their children for example. Wearing a fsking useless mask for something that doesn’t affect them doesn’t even enter the equation. Even if they could afford one, it would be reused endlessly and passed from mouth to mouth as needed, creating a far worse problem through bacterial contamination.
#MoronicTechnocrats
#FirstWorldProblem
#YaleWhiteImperialists
As we’ve know from July, the masks are only about compliance. It’s even admitted by the Zoe person linked to in your article. It’s just used as a reminder to people that a danger exists.
And yet the double speak coming out from government even suggests they are a way of lessening peoples anxiety and encouraging them out of their homes.
Total theatre.
So, actually reading the paper…
We’ve had public shaming, legal mandates for mask wearing — all for no significant benefit (normal cloth facemasks) and a measly 10% benefit for ‘the best’ approach (surgical facemasks).
Sure, 10% is 10% — but I’d note that this is of the same order as other ‘low benefit’ interventions but they’re not imposed by mandate. Eg, the PHE report on vitamin D found a likely 20% benefit, but they didn’t mandate that everyone take vitamin D, with fines for those who didn’t comply.
It is nice to pretend that if they’d have increased their performance proportionally with increased mask wearing but we don’t know this at all. Stick to the data.
They found no benefit whatsoever for those under 50, with marginal gains for those older than 50 — ie, once again we see the young sacrificing themselves for the old.
They also didn’t identify whether the mask wearing protected the self or protected others — it might have been that the vulnerable received direct benefit from wearing masks, and that it didn’t matter that much what everyone else did.
So, their overall findings are that we could either impose restrictions on all, for a rather low benefit for the vulnerable, or harsher restrictions on the vulnerable (maintain lockdown for them, not for everyone else, or possibly just mandate that only the vulnerable wear facemasks), for a similarly small benefit of the vulnerable.
The overall finding is that someone invested a lot of money in generating some entirely meaningless numbers for partially commercial and partially political marketing purposes. The reason this is being published is because these are the numbers that someone wanted to publish (or what comes closest to it).
This is an inherently non-repeatable experiment. Hence, there’s no way to verify or falsify the supposed findings. Hence, file as spam. Criticising this in more detail is a waste of time.
This seems to be a well intentioned study, but unfortunately the research milieu contains multiple uncontrollable variables which confound meaningful interpretation of findings.
There are some experts around checking study design.This study is rubbish and should be thrown in the bin according to them. .
https://boriquagato.substack.com/p/bangladesh-mask-study-do-not-believe/comments#comment-2764410 Another twitter thread on this study.
https://twitter.com/federicolois/status/1433123776208777227
So presumably they prechecked both villages for antibodies and T cell immunity etc confirming very low values for both in the intervention and control group to make sure natural / pre-existing immunity was not a confounding factor in the experiment. If not then the study is useless.
Surely a proper test on face mask efficacy would be to use two isolated living area – say two similar cruise ships. Have a mask mandate on one and not on the other, and then have some kind of marker dye aerosol released into the key public areas atmosphere of both ships maybe in the dining halls and corridors. The dye would have to be at the correct particle size and relatively binding to the skin hair etc so it can’t be easily washed away by other processes. At the end of a relevant period you then test every one for the amount of dye collected in their sinus, nose, throat, lungs mucus etc – presumably from some kind of swab sample
Such a test would then focus on just the relevance of mask wearing in a broader free but also controlled living environment.
How do you “randomly” select 600 villages to have the same health characteristics to within significantly less than a 6-8% deviation?