I actually think that you highlighted the wrong date: this paper was put online in June, received for review in July, approved in November, and published in December.
> Mitigating the spread of COVID-19 is the objective of most governments.
It's not a practical goal in the US, where COVID-19 is endemic.
Wearing masks is not going to accomplish anything, since it will just flare up again with our poor contact testing and tracing. In addition, likely half of Americans have no intention of taking a vaccine.
Heard in TV, all infectious disease numbers are down here this year. I wonder whether we will ever get back to touching non-family people, just to be friendly. Feel bad sometimes for kids growing up now. Not sure what long-term effects of distancing and so much obedience will be.
It will probably take time but we've been here before as human race while knowing how infectious diseases spread. I am a bit worried for the children in delicate age right now who need to learn right now socializing, seeing human emotions, train their immunity systems etc. Adults can have gap year or more, different with children.
> whether we will ever get back to touching non-family people,
I've been invited to three orgies, with dates TBD ("as soon as this ('gestures around') is over", one says). So maybe we'll have an entirely newfound appreciation of touch.
Or, you've not been infected by the idiota-virus that's spreading through apparently 90% of the population where everyone's trying their best to make up for lost time by such activities.
The Japanese have had more sensible traditions around (not) touching strangers I think. Wouldn't be the worst thing if those are adopted elsewhere. Hugging strangers like in the US or kissing when you meet people like in some places in the middle east is odd in comparison.
Devoid of any context, the implication that the Japanese "live like unemotional robots" comes across as unilaterally racist. Given that they are human beings, it is reasonable to assume most of their social conventions fulfill their emotional day-to-day needs.
In Jena there were about one dozend(?) infected people when masks were introduced. And the imaginary trend-change there doesn't even fit - it is too early. The paper talks about "announcement effect".
Fact is that other places with real outbreaks (>10 times more cases than Jena) never saw any trend-change from masks. It is even very likely that the effect is going in the other direction.
Even if you look hard, nowhere is it getting better - but there are quite a lot of places with massive trend-breaks in the wrong direction.
Reasons:
- Lures old people together without proper protection
- good way to transmit even without being infected
- breathing through contaminated masks is not good.
- contaminating mask is easy
Honestly, would anybody want doctors to walk around the city with their contaminated masks from hospital?
That's what you get from general mask use - Healthy people - exhaling virus. In some regions the trend-changes from mask mandates look like someone turned on the turbo.
Indeed, correlation between measures and outcomes is all over the place. We (Lithuania) are in the second lockdown since Nov 7th, masks are mandatory even outside, pubs/restaurants/cafes/gyms etc. are closed, all events canceled, there is restriction how many people can meet: used to be up to five, now only two — and we are still hitting our record numbers of cases. Slovenia had even public transport and schools closed, cases still climbing.
I did not check (and probably will not), but I have a suspicion that countries that had it "easy" in the spring are hit harder now. Those who were hit hard in the spring may have some kind of herd immunity among the most social active and hence have it easier now.
French person here : I do too. My hypothesis, is that people most likely to be exposed, and to propagate the virus ( health workers being the best example ) had a relatively high prevalence already.
Countries that made it well through the first wave suffer from underestimating the threat/overestimating their countermeasures in the second wave. Herd immunity has nothing to do with it, as evidenced by massive second waves in countries like Sweden or Belgium that didn't quite skip the first.
The underestimating/overestimating is actually quite easy to understand: everybody thinks to themselves that a slightly reduced amount of countermeasures should be sufficient compared to the first wave, because it's less of an unknown now. And they might even be right about it! But the same process happens on multiple levels in parallel while everybody assumes all other remaining equal and then they compound. Relative to countermeasures in the first wave, governments weaken executive orders this time (by an amount that might be appropriate all other parameters being equal), regional administrations weaken their execution (by an amount that might be appropriate all other parameters being equal), private organizations, from corporations to knitting clubs weaken countermeasures in their procedures (by an amount that might be appropriate all other parameters being equal) and individual weaken both their personal protection habits and their adherence to all those rules, by an amount that might be appropriate all other parameters being equal.
Nobody can revert all those compounding weakenings, the only single point of correcting for them is at the top level: in the second wave, you need considerably stricter government rules to get the same effect. And even they are only corrected in a reactive way, when the numbers become too bad, when the wave becomes too high. Hence the almost universal big second waves.
> countries that had it "easy" in the spring are hit harder now
Not all. At least here in Norway we had about double the confirmed infection rate on 12th November (771) that we had in the early peak on 26th March (423), 7 day averages. We are now down to 110 per 100 k people (14 day average).
But on the 9th March 17% of tests were positive, on the 18th of November it was 3.5%, now it is only 2.2%. But we test a lot more people now; 6k tests per day in the early peak in the spring, 31k in November, now about 90k per week, roughly 1600 per 100k people.
Here the second wave was regarded as rather serious but the threshold for regarding things as bad is rather lower than is usual in Europe; in comparison with most of our peers and neighbours we have it pretty good.
Are people actually following the measures? If no one ever meets more than one other person per day, it's astounding if the number of cases is still rising.
Nobody is getting covid via surfaces. It spreads via socializing. Millions of people are still visiting each other behind closed doors every day as if things were normal in EU.
"The virus can also spread after infected people sneeze, cough on, or touch surfaces, or objects, such as tables, doorknobs and handrails. Other people may become infected by touching these contaminated surfaces, then touching their eyes, noses or mouths without having cleaned their hands first."
Well, how many follow the law? That's a pretty big problem. If you replace a big party with 100 people, with ten smaller parties with ten people, you probably end with a similar amount of infections (maybe even more?)
Most do. There are substantial fines, if you do not obey. Also, when everything is closed there is not much you can do anyway.
The problem is that our institution which was supposed to do contact tracing is a mess and totally unprepared for the amount of work required. So contact may not get notified at all or notified with a 7-10 days lag.
>If you replace a big party with 100 people, with ten smaller parties with ten people, you probably end with a similar amount of infections
I don't think that is a correct conclusion. It doesn't behave linearly.
"We can think of disease patterns as leaning deterministic or stochastic: In the former, an outbreak’s distribution is more linear and predictable; in the latter, randomness plays a much larger role and predictions are hard, if not impossible, to make. In deterministic trajectories, we expect what happened yesterday to give us a good sense of what to expect tomorrow. Stochastic phenomena, however, don’t operate like that—the same inputs don’t always produce the same outputs, and things can tip over quickly from one state to the other."
The public needs to truly learn how to wear masks, which masks to wear, etc. I bet you the efficient of, say, cloth masks is super low due to the fact that people wear them incorrectly, don't wash them properly, keep touching them, etc.
I believe that touching them, wearing them too long, imperfect (but not outrageously bad) fit are merely imperfections, not nullifications. These things are a bit like stripping off a few nines from service availability vs shutting it down completely.
Preventing these imperfections is extremely important in a very high infectivity environment like a hospital's Covid ward, but they don't really change the masks' impact on the epidemiologics of supermarket trips.
A protection level that only shifts the average time to infection of a Covid ward's staff from Monday to Thursday would be terrible, but the same level of protection added to otherwise unprotected supermarket goers can easily reduce the supermarkets' contribution to the R value from heavy to insignificant.
Yes, of you do not impeccably follow the procedures required by medical staff in high infectivity environments the small remaining risk of defense penetration will rise by a high factor, no, the remaining protection will still be much better than no mask.
Looking at the 7 day average of daily deaths: in Lithuania since Nov 21 it oscillated between 15 and 16, and that started exactly two weeks after the introduction of the measures the growth in the number of deaths stopped. We also know that the deaths are lagging indicator of measures: before people die they have to pass the incubation phase, get sick, get worse and die, which should take a few weeks at least.
Based on that data, I can conclude that the measures do show some effect.
The effect is less observable in the "cases" data, where the daily number of cases indeed grew since 7th, but even there there should be a lag of a little less than a week from the point the measures start (it takes time for the people who were infected before measures to incubate and be able to be tested positive or get sick). Interestingly, that is what we see there: there was growth in 7-day average daily cases until Nov 13, then only on Nov 21 that number gets higher again. Which indeed points to the possibility of measures working less from that point on, but at least the growth since Nov 7 is also obviously lower than it was before, which is also what can be expected if the factor that the newer measures bring is low enough that the speed of the spread is reduced, but not high enough to reverse it.
So there are signs that the measures, as much as they are followed, have some effect, but sadly not enough to reverse the trend.
Slovenia, on another side, has practically the same amount of daily cases for the last 30 days, when 7 day moving average is calculated, but the equvalent calculation of deaths show flattening only between 17th and 26th, and then there's growth of daily deaths again. As the average number of daily deaths is the statistics which is less influenced by the number of tests performed and it's independent on the success of contact tracing, that shows that in Slovenia the spread is still not under control, and additionally, that the month long flattening of the daily cases could mean that there's a bottleneck in health system -- that relatively fixed number of persons could be processed daily, but that due to the priorities those who are processed are, through the time, the patients with worse conditions, resulting in continuous growth of deaths (and the last is just a hypothesis which can be verified or rejected based on the exact related information from Slovenia).
Your comments regarding contamination do not sound plausible to me. If you're infected, of course your mask will also be contaminated by SARS-CoV2, but you hopefully will not distribute as much of it around you as you would without the mask. If you're not infected, the only way to contaminate the mask with SARS-CoV2 is to be exposed to infected people exhaling it. And in that case it's better for your mask to become contaminated than to inhale it unfiltered.
As for the "announcement effect", I did start wearing a mask when the mandatory mask policy was announced, before it became actually active in the following week. And I wasn't the only one that did that, so some announcement effect is very plausible to me.
The curve flattens naturally at some point, always after “something” has been done. That does not mean these two things are related to any significant degree.
The number of of actively infected non-quarantined people is relevant. Take a look at RKI-dashboard for Jena. This Jena paper is a serious fake.
I think mask measures are not working correctly - all the masks are way too dirty - effects are most likely going in the wrong direction.
Getting good data to evaluate measures currently isn't easy. Some curves using "reporting date" look seriously different than curves using "date of death".
In Jena there were about one dozend(?) infected people when masks were introduced.
Already wrong, the very article shows that Jena had about 145 verified cases in April 6. And test availability was absolute shit in March/April. It still isn't much better now, but from the relation of cases and deaths in the first and current second wave[0], we can infer that current testing is about 3 times that of April.
Actual cases therefore were at least about 450 in April 6, if we generously assume everyone who is positive gets tested right now. Jena only has a population of 110k BTW.
In April, more than half of infections in Germany happened in nursing homes and hospitals. Also, iirc it was very unevenly spread across regions (also consider that often it was superspreader events that drove up the numbers, it was not a even distribution across the whole population). That makes me suspicious of the paper, as there may be many confounding variables, and small sample sizes. People may also have started using maskes or other measures before the government mandate, especially the professionals in nursing homes and hospitals.
If you are looking for convincing evidence in favour of mask wearing - this paper is not it.
It bases its conclusion on a few hundred cases in the German city of Jena back in April. In fact, the authors themselves apply the same analysis to other cities over the same time period (figure S15 in the supplementary material) and those plots show hardly any effect.
However... if a paper claims to support X and the paper is bad, then that does not mean that X is incorrect. And given government advice around the world, it seems pretty clear that masks are understood to do more good than harm.
I used 'understood' because it is what I believe the scientific consensus to be. Since I do not use this for anything else, there is no 'appeal to authority' in my original comment.
That said, let me double down and state that I wholeheartedly recommend using the scientific consensus as a prior for your opinion on any given topic. :)
An appeal to authority is a good reason to believe something if the authority can be understood to be knowledgeable. It's especially useful in cases where your readers can't all be expected to understand the nuances of the decision making involved and you want to avoid appealing to emotions (which works better). What basically never works are appeals to logic, frequently even here (a place which explicitly stimulates it). The reasons for why it doesn't work here (miles of text with pedantic arguing, usually not a lot of substance) are different for why it won't work in public (people don't feel like doing that with you, usually) but they are there.
Especially in a case such as this an appeal to authority can be useful, as there is a big bad-faith storm of "discussion" surrounding the subject that really isn't doing anyone any favours.
True, but you can never use it to prove that something works, especially in a case like this where governments are acting under time and information constraints.
It is not enough for the authority to be knowledgeable, their incentives must also be aligned. If people appeal to the authority to do something, then it may do whatever is expedient regardless of merit.
With limited knowledge, I'm inclined to go along with measures that are low cost and have a plausible explanation wrt. effectiveness. That being said, if the mask situation has shown us anything, it's that the authorities are neither trustworthy nor competent.
When you trust your doctor or lawyer, you're also appealing to authority. It's not wrong for a person on the ground to look to various national/international institutions as signal (evidence) for a hypothesis, and to adjust as their life experience guides them.
It would be if the reason the advice was given by governments was NOT at the behest of doctors/scientists fighting the pandemic. However it is, so in this case the governments are just the messenger best able to broadcast the message and ensure a high level of compliance.
It's... Either badly named or applied without nuance. It's not about situations like "they're an expert on X, therefore I trust their opinion on X". Instead it's for "they're an authority on something, therefore if they have opinion on X, I should trust it".
It’s not a crap fallacy, it just doesn’t always apply. It’s a fallacy only in the case that you are trying to establish a strictly logical argument (in the mathematical sense). “You should do this because that expert said so” is a rational argument, not a logical one.
Your are conflating what is practical with what is true in logic and argumentation. It is practical to accept our doctor's diagnosis because we trust that the medical system produces competent doctors and because of constraints on our time. If you claimed that a diagnosis must be true because it came from a doctor then you would appealing to authority.
There cannot be "convincing evidence for mask wearing" for most thresholds of "convincing", can there? Since no clear difference in infections or mortality has been observed between places with different mask rules (and timings of their imposition), the effect must be either very small (in either direction) or none.
https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6947e2-H.pdf isn't subtle. You can make the argument that it might not be the wearing of masks specifically that's responsible for the difference here, but the weaker argument - that it's worth being the sort of area that will introduce mask wearing because whatever is going on is correlated with it - still works.
Exactly. It's hard to see how masks themselves could have a negative effect. If they have a positive effect caused by people being more conscious of the current situation and keeping a greater distance, or not going out at all because having to wear a mask is a burden, so what? Worst case is they are neutral all things considered.
It may be hard to see how masks themselves have a negative effect, but it's easy to see how mask wearing as a medical intervention in the real world could. All it would take is people being willing to stand slightly closer together or take slightly more risks because they believed masks were effective protection.
As a counterpoint and to reiterate the parent comment's point, masks are a stark visual reminder that you need to practice other measures like social distancing and going out less. I'd be willing to bet that masks increase likelihood of practicing safe pandemic measures due to a "top of mind" effect rather than decrease them due to a false sense of safety.
That's why the message must be clear: even if it protects a single wearer just 20%, it can provably have huge benefit to everybody, but only if everybody does it (1) while all that doesn't mean that other measures could be avoided (2), especially if R raises in spite of one single measure.
Very interesting! I'm a bit confused about the data/graph that shows their main conclusion, anyone know why:
They use a 7-day rolling average and general consensus is that covid has a 3-14 day incubation period. Combining these two would indicate that the mask's effect should be gradually becoming stronger starting ~4days after introducing and reaching peak effect after 21 days in the graph. The graphs show a strong effect after 4 days and remain constant after that. Does that undermine the conclusion or am I seeing this wrong?
They use a linear regression while infection is an exponential process in my understanding, doesn't this undermine the regression?
The description of S15 gives a plausible explanation of why the effect is much less for some of these city than for Jena. Of course this is speculation but this doesn’t mean that fig S15 disproves the paper’s finding. And for Jena the effect is extraordinarily strong, and well controlled for. I’m not aware of any alternative explanation (to mask-wearing) which could explain this effect, and until I hear such an explanation I consider this strong evidence for the effect of mask-wearing on COVID-19 transmission. This study isn’t the only evidence for the effectiveness of mask-wearing but it’s certainly part of the overall evidence, and I’d like to hear better arguments for calling it “bad”.
I found someone on the internet who said they prayed for Weimar, a smaller neighbor city of Jena. Luckily you can use the same mechanics of the study to grasp the effects of their prayer. It worked similarly well[1] as masks in Jena[2].
Jena is a single data point supporting the effectivity of masks (there could be indirect effects at work as well, i.e. people better grasping the severity of the situation).
The sophisticated average that they use as comparison makes it appear to carry more confidence than it does.
> And that is why post-hoc hypotheses aren’t valid.
I agree on this. Can you point to where they announced the study on April 6th or before? Or did the decide to look at Jena only after the data was available?
How is that not a post-hoc hypothesis?
Of course, both general hypotheses of masks and prayer predate Covid19.
> It does not, however, invalidate this study.
No. The study contributes a single data point in favor of masks, but is not very convincing (in that the authors did not look deep into contradictions and alternative explanations) and of course not conclusive as the bad title makes it appear.
The study was designed to tease out mask-wearing by attempting to control for other factors via its study design. — They did this specifically by comparing a mask-wearing city with a synthetic control unit based on reference populations without mask-wearing rules. So the hypothesis “mask-wearing helps” is, by design, not post-hoc.
You’re right that it’s a single data point (though with a strong effect size). And, being an observational study, it simply can’t exclude all confounding factors, and will never approach the strength that a controlled study could. Nobody is disputing that. Interpretation of observational studies always needs to be tempered by the reality that it’s impossible to control for all confounders.
But within these given constraints the study essentially provides as strong evidence as could reasonably be expected (unless the study has a flaw that I’m overlooking and which, as far as I know, hasn’t yet been pointed out elsewhere). Their design of the synthetic control is statistically sound and controls for a very large number of reasonable confounders. And, contrary to the claim in the comment I’m replying to, data from other cities does not invalidate the study’s findings. As far as I can see, the study’s inadequacies are all due to external circumstances and not because it’s a bad study.
> And given government advice around the world, it seems pretty clear that masks are understood to do more good than harm.
Until sometime in March or April, government advice all around the western world was that masks in community settings are ineffective and possibly dangerous (due to improper handling).
Usually when these agencies change position or announce a new position, the decision is accompanied by a properly referenced whitepaper that lays out the evidence for the new position. This hasn't happened here.
Massive confounding factor here is that starting around April seasonality into summer was putting massive downward pressure on the epidemic across Europe anyway. There's no mention of attempting to control for this effect in the paper.
As it happens the UK's second wave kicked into exponential increase around mid August - the only major public health policy intervention coincident with this was mandatory mask wearing. So yeah.
Not only that, but back-projections of R0 across summer show a distinct upwards turn from below 1.0 at the start of August, exactly when EOtHO started.
Anecdotal, but my city made masks mandatory both indoors and outdoors about a month ago with €250 fine for non-compliance. Other measures roughly stayed the same. Prior to that, roughly one in every 88 people were considered to be active cases. Today, that number is one in every 121.
Of course this is just my rough calculation (latest population census divided by the number of active cases), and the number is expected to improve somewhat as the amount of population with antibodies increases, but I'm pretty sure masks help.
> Massive confounding factor here is that starting around April seasonality … was putting massive downward pressure on the epidemic.
That’s wrong, the opposite is the case. The study controls for this by looking at a synthetic control over the same time period, which consists of other populations without mandatory mask-wearing. It’s an observational study so it can’t control for everything but it does control for seasonality, even if “seasonality” isn’t specifically mentioned in the paper.
Keep in mind that these are two slightly different things. Masks might not reduce your personal risk of infection, but they might reduce the risk of you infecting others. In either case, you would see a reduction in the total amount of transmission.
Are people still confused that the reason you wear a mask is not to protect yourself directly, but to protect others thereby indirectly protecting yourself? It seems so, because in the west people are still arguing about wearing masks, and doing these inane studies, while in Asia people wear masks and go about their business as usual.
Yes, you're right of course. "The west" is a big place with many different moving parts, just like Asia. So things aren't the same everywhere. It's just that there are many western countries where the arguments about mask wearing and social distancing are still going on while the pandemic is raging while in most of Asia that isn't happening and the pandemic has largely been nipped in the bud.
And Thailand and Taiwan (I think) and maybe a few other countries. I think that is certainly a factor.
But something seemed to change, at least here in Thailand. Although mask wearing was normalized in cities as self-protection against air pollution, many/most people seemed to come around to the notion that mask-wearing was a collective effort to mitigate the spread of the virus. Seems like a cultural effect - more collectivist rather than individualist thinking.
Yes, very much so. From my experience people wear masks and visors to protect themselves. I honestly do not think the average person view wearing a mask as something they do to protect others. It's a little weird, because at the same time people seem very conscious about the risk when people around them can't or won't wear a mask.
At least in Denmark I don't think it's communicated very well why you should wear a mask. The government says "wear a mask" so the majority wears a mask. It's great that we have that level of trust in government, but it also sometimes mean that things are communicated as well as they should be.
Exactly, the whole argument is dumb. Until it's proved that masks don't reduce transmission, they should be mandatory (and freely distributed by governments). The burden on the wearer is so small, and the potential upside so large, I don't really see why there's any debate at all.
The fact that places in the world (like Adelaide and Melbourne) even considered lockdown before requiring masks was incredibly lazy and/or negligent.
Does one not need to be infected to effectively transmit the virus? I.e. if you're infected your body is actively multiplying the virus. If you're not infected, then you're just passing on whatever virus you happen to be contaminated with. There's a massive difference between the two I should think.
> given that a large Danish study says that masks doesn't reduce your risk of infection in a significant way
That’s not what this study says. What the study actually says is that they found wildly huge odds ratios in their confidence interval. The only “conclusion” that can be drawn from this is that the study is inconclusive.
To explain further: to positively conclude that there’s no benefit to mask wearing, the study would have had to produce a small confidence interval around zero effect. In reality, its 95% confidence interval is between 46% reduction to a 23% increase in infection. Any number between these bounds is compatible with the study results. That’s all over the place, and doesn’t allow any conclusion.
One thing I noticed with nearly everyone, both in the real world and in tv, is that people still don't seem to understand a simple issue: wearing a mask 90% of the time is more or less as good as wearing no mask at all. If you're sitting in a room or flight with a mask but open it to drink water and eat food, you've mostly ruined all the protection you tried to gain with the mask. You only need one drop of yogurt to spoil a vat of milk, this is no different.
I'm pretty sure 90% of the people wearing masks don't do it because they're worried about themselves. They do it either plainly for legal reasons or because they believe it help protect others.
If I were that concerned about my own health, I wouldn't be wearing the same unwashed cloth mask for weeks. (I'm vaccinated against a whole bunch of pneumococcus and respiratory diseases)
People are not surgeons. The goal is not to maintain a sterile environment. The masks people generally use are not even rated for that.
The situation is simple. With airborn virus, people will get contaminated when they come into contact with droplets containing virus. Given the typical viral load of people having Covid-19, the issue will mostly be with large droplets. These droplets are stoped by masks. Of course, you are going to emit droplets when you are drinking or eating but far less than than you would have not wearing a mask at all.
The point is not to gain protection. It's to limit your chance of contaminating other people if you are asymptomatic.
So desperate to try to prove a point when science says repeatedly shown improperly wearing a mask is worse than not wearing a mask and everyone I see in the public is in violation of MOPP
Refusal to engage with Gish gallop [1] does not validate the claims you’ve linked. This isn’t “wrongthink”, it’s a sign that you’ve posted a laughably bad source.
Those charts do not show any information regarding the effectiveness or otherwise of mask wearing.
There is no information about what proportion of the populations actually wore masks, how close people actually got to each other, what the population density and degree of urbanization is, etc.
In Norway we mostly have not had strict lockdowns and have not had compulsory mask wearing until very recently and our infection rates and death rates are lower than most other countries as shown on the charts. But you need to be careful how you interpret that; Norway has a relatively low population density and a large proportion of jobs are of a type that can be done at home. So pretty much everyone who could work from home immediately did so (a lot did anyway). We also have a strong tradition of solidarity; unlike the UK 'We're all in this together!' is not just a slogan.
Our government has also been largely consistent in the advice that it has issued and, with a couple of exceptions, avoided overreacting which means that people are willing to adhere to the rules even though most are just advice and not enforceable.
Most charts from all sources, and especially things like the Federalist, should be taken with a shovel of salt; not because of what they include but because of all the information that is omitted.
I looked at the chart titled 'Avoiding going to work' and was bemused because I couldn't see the line for Norway, where I live. When I turned of the Asia, and US I was able to see it. It would be interesting to know the expected error of the surveys that were used to generate that because the impression I have is that vastly more than 18% of the Norwegian working population is working from home. In fact even in normal times a lot of people work from home a significant fraction of the time.
So I am still of the opinion that such charts don't tell us very much and in particular they do not tell us how much we can rely on them.
And one last point: there is a chart showing that 40% of Norwegians say that they are 'Avoiding physical contact with tourists'. What tourists? There have been essentially zero foreign tourists in Norway since March and internal tourism has practically disappeared a well so what meaning, if any, can be associated with such a statistic.
Having actually gone to the trouble of reading all the papers linked in the above article, here's my take:
1. The article attacks a straw man, in that it suggests that masks are supposed to be a cure-all against Covid-transmission. I have not heard this seriously claimed - rather, masks are only one of a range of responses. (Indeed, by far the most important and effective reaction seems to be reducing the number of personal contacts - masks are only intended for those situations where this is not possible.)
2. Masks can only be effective where they are worn. At least in Germany, recent data suggests that most infections are taking place in private settings - where masks are not compulsory (and usually not worn). This could be used to argue both ways: either that the widespread use of masks in public has been successful in reducing infections in the public space, or that the continued widespread infection in private settings means that wearing masks in public is irrelevant. (I do not have the data to meaningfully compare these two claims.)
3. The evidence we have on the effectiveness of masks does seem to be pretty patchy, with many studies showing methodological problems and coming to different conclusions.
4. Generally, the protection effect for the wearer seems to be low or non-existent. However, while not significantly reducing inhalation of virus particles, masks do reduce droplet exhalation (and so protect others in the vicinity of the wearer). I.e., there is an indirect protection effect.
5. It seems to be true that masks are not very effective against aerosol infection (preventing this requires other measures, specifically good ventilation). However, this cannot be used to argue that masks are superfluous, as droplet infection (which masks do help with) is another important transmission vector for Sars-CoV-2.
TL;DR Masks are not a cure-all. They must be used in conjunction with other preventative measures, or they are useless. However, they are probably effective as part of such a larger package.
My uneducated perception is that the most effective factor seems to be the people's own adapted behaviour itself.
When the situation gets worse then not only the top smartest people but also larger masses begin to take it more seriously to protect themselves, keeping distance, and omitting trips and reducing contacts.
This obviously doesn't apply to careless people or "non-believers" but they wouldn't be much affected by regulations either. So there's always (hopefully) a minority of the population where the virus can spread more easily but once the majority successfully does react it will show positively in the growth curves within about 10 days.
Coincidentally this is also the same time where governments impose strong recommendations or even enforce counter measures. Mandatory shutdowns of cafes and restaurants might seem an effective ordinance but the truth is that by that time most people already refrain from going to crowded places such as cafes and restaurants. And usually there's at least a few points of empirical data from neighbouring countries that those same counter-measures alone won't help limiting the growth if the people themselves aren't in it. It only takes one mask-wearing country to not recover from infection growth in order to make it questionable whether masks help much at all.
Keeping distance seems much more effective than masks. In reality, I've seen that when masks became common place people partially reverted back to flocking together and not respecting a good radius of personal space anymore. Masks probably won't hurt if you need to be close to other people but it would be much, much better to keep the distance in the first place.
The extra care makes a difference. Anedoctally my family did not catch cold or flu since first hearing about the possibility of the pandemy. At least not symptomatic.
> When the situation gets worse then not only the top smartest people but also larger masses begin to take it more seriously to protect themselves, keeping distance, and omitting trips and reducing contacts.
> Keeping distance seems much more effective than masks. In reality, I've seen that when masks became common place people partially reverted back to flocking together and not respecting a good radius of personal space anymore. Masks probably won't hurt if you need to be close to other people but it would be much, much better to keep the distance in the first place.
I've noticed this when visiting the shops daily when I get my lunch. Before mask were mandated, almost everyone kept each other at a distance. Since mask wearing people have barely bothered.
I've mentioned this to friends on my discord server. Some are from Europe or elsewhere in the UK and they have noticed the same.
Is it not possible that this is a time-related effect rather than a mask-related one? As the pandemic has gone on over the last 6+ months, people have grown tired of the measures, especially given the low mortality rates in most places. For your point to be true, you'd have to compare mask wearing and not mask wearing practices at basically the same point in time rather than weeks or months apart.
Counterpoint: in the US I mostly see people who don't wear masks not keeping their distance and still wanting to shake hands because they simply aren't afraid of Covid at all. The mask-wearing people I see here are more likely to practice distancing and reduced contact.
Germany did not wear masks on the first shutdown in spring (same as Danmark and Sweden) - the were not available and they came as the spread already went down heading summer.
As for the headline, Germany has a strict shutdown at the moment.
Germany does not have any strict shutdown. National mobility isn’t limited and all shops are open. The gathering of people is kinda limited, but nobody controls it.
The authors compute a sophisticated average of German cities and compare the weighted number of positive SARS-CoV-2 tests to the city of Jena for a timespan of one month starting just before masks became obligatory there (6th April). Masks did not become obligatory elsewhere and roughly around the mask obligation new positive cases drastically reduced in Jena whereas the weighted average shows no such effect.
EDIT: moved my doubts in the study into extra comment.
If you think the summary is wrong, please leave a comment pointing out in which way, after downvoting.
Since I seem to get downvoted for adding doubt to the paper in my comment, I move it here:
The study does not look into other east German cities like Weimar[1] or Rostock that showed a similar drop in positive tests without mask obligations.
New positive tests in Jena recently reached an all time high. [2]
Thanks for the summary, this confirms what I already suspected, which is that these kinds of studies are pretty much useless to correlate anything with anything.
On top of that it seems the study hypotheses for these papers are clearly biased towards proving a positive correlation between infections and mask use, even though one could do exactly the same kind of study in many other parts of the world where infections exploded along with increasingly expansive mask mandates. For example France and Spain, where numbers only started to go down after they went into second lockdown.
No matter what you think of mask effectiveness, cherry picking statistics is bad science, and so far that’s all I’ve seen as far as the ‘masks are effective’ studies go.
I have to challenge this assessment from the article. Masks did become mandatory elsewhere. Mostly in targeted spots in the cities such as the zeil in Frankfurt and Potsdamer platz in Berlin and I can tell you that it is met with strict enforcement and that people are adhering to the rule ardently with very few exceptions. The article and much of the science leaves much to be desired.
It is my opinion that the “all or nothing” pro mask people are actually obstructing the science. Their intolerance to confront or question evidence that is contradictory or unexplained anomalies in the data such as this article is dangerous to actually having the right response to covid leads to nonsensical draconian rules like the California mayor suggesting requiring wearing a mask 24 hours a day and only removing between bites when eating.
Seems pretty much a worthless analysis to me. Facemasks were introduced in April, infection went down in April, masks worked! Except that this virus seems highly seasonal and spring also came in April!
Where are the "if it's not a double blind study where you isolate a variable, you haven't proven anything" people when we need them!
Exactly the same argument against waiting 3 months for randomized studies to use a drug against an epidemic. If only one could press the pause button on the epidemic.
I find it weird that science can't conclusively answer the question "is wearing a face mask going to significantly reduce the spread of covid". It's been nearly a year since this was a known disease, and beyond that masks have been around for a long time and they are used by the medical community to some degree. How can we not know based on the shear mechanics of these two entities whether this is effective?
I feel like every other day there is a new study or report that refutes the study or the report I just saw from another respected institution. I'm not surprised people are frustrated at this problem. As an example, look at this study that was posted just 13 days ago on HackerNews: https://news.ycombinator.com/item?id=25159583
The Danish study is not good. They're not controlling for mask/no mask, they're controlling for suggestion to use masks (and they didn't even go back and ask "did you wear a mask or not).
In the end it seems people are more worried in publishing hastly prepared experiments/results than worrying about getting to the bottom of things.
> How can we not know based on the shear mechanics of these two entities whether this is effective?
It seems obvious to me that masks have a positive effect. A mechanical barrier is better than nothing. "Oh but influenza" Influenza and Coronaviruses are different
Doctors and Dentists don't use masks because they think it's funny or comfortable
There are different claims -- if one is "frustrated" it's only if one doesn't even attempt to distinguish what's written where. Reading more than just the title in the link you've given:
"The results could indicate a more moderate degree of protection of 15-20%" to the wearer.
"The findings are consistent with previous research. Health experts have long said a mask provides only limited protection for the person wearing it, but can dramatically reduce the risk to others if the wearer is infected, even when showing no symptoms. Preventing the spread to others is known as source control."
Now consider the following: if the "current" R number (the average of how many people are further infected by one infected person) in some environment is 1.2 that still results in the number of infected per day exponentially(!) increasing. Example: after the sequence of 10 infections with R 1.2 there are 6 infected, after the sequence of 20 -- 38, after the sequence of 30 -- 237 and after the sequence of 100 -- 82 million people infected, starting from just one. It is estimated that it takes just a few days for one sequence. Taking that number to be around 3.6 (it doesn't have to be that number, it's just to take some convenient number as an illustration) means that 100 sequences can be imagined as one year. So 82 million in one year.
Now if every wearer is protected only 20%, it can appear to the wearer who doesn't understand math that he should not wear it. However, reducing current R number from 1.2 to 1 means that the number of infected per day doesn't increase at all but remains constant. Example: starting with 1 infected, after the sequence of 100 there are just 100 infected. Using the same convenient number, after one year, still just 100 infected.
That, in turn, means that if everybody wears it, everybody wins: allowing exponential increase of infected will result in everybody becoming infected, whereas the constant number of daily infected could guarantee that most don't become infected before they can be vaccinated.
Not to mention that if the number of infected per day can be kept constant some other kinds of measures
(lockdowns with closures, bad for economy) could be completely avoided, especially if it is achieved at some low level. Which means that it can be of immense benefit to the wearer to wear the mask as much as possible even if he increased his own direct protection in some specific situation for mere 20%! Moreover, the benefits are dependent on most others also wearing the mask! If he's doing that alone, than it's in vain -- he alone can't change R for the whole population: his highest interest is to convince others to do the same.
Being willing to understand math and to read carefully helps.
Exactly. I liken it to multiple layers of security. Almost no single layer is 100%, so you stack. In covids case, masks, distancing, and hygiene are the layers. None are 100% on their own (unless you live alone and have zero interaction), but taken together on a population level they can work to lower R0 below 1.
Side note, I recently read a good book that addressed why people have such a hard time with percentages. People tend to take numbers like 20% and think 0 and 80% and think certainty.
Yes, I agree, only it's not about the percentages alone. I'll quote from my post from April (1) which was already in the context of Covid-19, where I quote the start of the presentation by Al Bartlett:
"It's a great pleasure to be here, and to have a chance just to share with you some very simple ideas about the problems we're facing. Some of these problems are local, some are national, some are global.
They're all tied together. They're tied together by arithmetic, and the arithmetic isn't very difficult. What I hope to do is, I hope to be able to convince you that the greatest shortcoming of the human race is our inability to understand the exponential function."
That's why when some hear that R=1.2 can be catastrophic and R=1 can be fine they just switch off. And there is exactly that "only 20% percent" difference.
But many developments in nature that work against humans have exponential behavior, including the stuff that humans do.
Somebody once named the video of that Bartlett's presentation "The Most Important Video You'll Ever See" and in this case it's not a clickbait.
How useful masks are depends on so many things. What are they made of is just a small part. Do you know how to use the masks you have? Do you have a beard? Or just a one day stubble? Some masks consists of one layer of fabric and even three-layer masks can't be worn endlessly, they can be washed but not infinitely. Some people wear the mask just covering the mouth, not the nose. Or upside down so the metal strip that seals around the nose is under the chin. I'm no expert in how to use masks but I see dubious things the whole time, both in reality and on TV.
Masks are a pointless waste of time when it comes to containing the pandemic.
Yes yes, I know. Just let me explain.
Masks DO help prevent the range particles can travel when you breathe. I'm not arguing that. The fact is, however, they're useless in comparison to the ACTUAL champions of prevention.
And that would largely be hygiene. I'm willing to bet 99% of you reading this do not clean your fingernails properly while washing your hands. Which is fine, THAT'S how good soap is. Doing it poorly is orders of magnitude better than not doing it all.
Is the same true of masks? Absolutely not. If you don't wear a mask properly, it's useless. It gets worse with specialised gear, like the N95s. You need to be trained on how to fit, test and adjust that. Have a beard? Not gonna work. Small leak out the top? Nope, it's buggered.
You ever notice how developing nations struggle with higher infant mortality rates, caused by preventable communicative diseases like cholera? It's because they don't wash their hands with soap. Soap is literally a life saver [0]. There's a damned good chance it's saved you a nasty infection, if not your life, directly or otherwise.
It's strange to me we understand why gloves aren't effective, but somehow that logic gets lost when masks pop up. If you don't know how to stop yourself from contaminating your environment, you're really not getting anything from wearing a mask. Or gloves. Or scrubs.
China is a fantastic example of this. They just ignored the whole "human rights" problem and went straight to welding people into their own homes [1]. Highly effective. Conversely, they'd been wearing masks for a long time because of their air pollution. Clearly not very effective. (The point here is the behavior and the objective is more important than the mask).
Here's what we should be focusing our energy on:
1. Social Distancing
2. Wash your hands properly [2]
3. Coughing etiquette
4. And then, finally, PPE including masks. If you don't know how to use gloves properly, then don't waste your money (because we all seem to forget economics is also a problem to solve here).
JUST focusing on masks won't cut it. Rather focus on JUST washing your hands then. You will see a much larger return on investment there. That evidence is also irrefutable. Compare the rate of death from communicable diseases in areas where washing with soap is prevalent to areas where it is not. SARS-CoV-2 has a lipid bi-layer, so soap will destroy it.
[2]: https://www.youtube.com/watch?v=xLIFT9xoWSQ the key bit here is scrape your nails against your hands when they're full of soap, so that the soap gets UNDER your nails too. Germs are tiny, and everywhere. So get em good
Hand-washing and coughing etiquette were emphasised strongly at the beginning of the pandemic, before mask-wearing. But at the moment it actually seems that contact infection is at most a minor — or virtually irrelevant — mode of infection. Hand-washing therefore almost certainly ranks way below mask-wearing in terms of effectiveness^1. As for the rest of the list, social distancing is strongly emphasised but incredibly hard to do in practice. It’s an extremely costly intervention, because it affects the economy both directly (workplaces) and indirectly (restaurants, cinemas …). And yet, notice how many countries still practice strict social distancing rules (albeit inconsistently and often not based on the best evidence).
And as for coughing etiquette, I can’t remember when I last heard somebody cough or sneeze when out. I’m sure it happens (after all, it’s sometimes unavoidable) but it has definitely gotten much rarer. In sum, it’s a very strong claim to say that “masks are a pointless waste of time”, and almost certainly wildly off the mark.
^1 Of course hand-washing should be practiced nevertheless, because it also prevents other infections, notably GI infections. But paradoxically excessive hand-washing also has negative health implications: soap and alcohol destroy the skin’s protective layer and dry it out, and the mechanical action of hand-washing exacerbates this through abrasion, which causes micro-lesions, irritation, and increases the risk of catching infections. And unlike for mask-wearing we actually have very good evidence for this. We don’t yet know the exact consequences, but the NHS has noticed a strong uptick in dermatological conditions since the beginning of the pandemic, some of which are serious. (Here’s a publication on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102542/)
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[ 4.9 ms ] story [ 182 ms ] threadThe paper is open access by the way.
June version: http://ftp.iza.org/dp13319.pdf
B: Face marks ACTUALLY increase germs/infection MORE
C: Its a global convid PLANDEMIC and Hoaxdown by 170 nations
Look at the actual DEATHS compared to yearly deaths of FLU and other death rates
It's not a practical goal in the US, where COVID-19 is endemic.
Wearing masks is not going to accomplish anything, since it will just flare up again with our poor contact testing and tracing. In addition, likely half of Americans have no intention of taking a vaccine.
I've been invited to three orgies, with dates TBD ("as soon as this ('gestures around') is over", one says). So maybe we'll have an entirely newfound appreciation of touch.
In Jena there were about one dozend(?) infected people when masks were introduced. And the imaginary trend-change there doesn't even fit - it is too early. The paper talks about "announcement effect".
Fact is that other places with real outbreaks (>10 times more cases than Jena) never saw any trend-change from masks. It is even very likely that the effect is going in the other direction.
Even if you look hard, nowhere is it getting better - but there are quite a lot of places with massive trend-breaks in the wrong direction.
Reasons: - Lures old people together without proper protection - good way to transmit even without being infected - breathing through contaminated masks is not good. - contaminating mask is easy
Honestly, would anybody want doctors to walk around the city with their contaminated masks from hospital? That's what you get from general mask use - Healthy people - exhaling virus. In some regions the trend-changes from mask mandates look like someone turned on the turbo.
[1] https://www.worldometers.info/coronavirus/country/france/
The underestimating/overestimating is actually quite easy to understand: everybody thinks to themselves that a slightly reduced amount of countermeasures should be sufficient compared to the first wave, because it's less of an unknown now. And they might even be right about it! But the same process happens on multiple levels in parallel while everybody assumes all other remaining equal and then they compound. Relative to countermeasures in the first wave, governments weaken executive orders this time (by an amount that might be appropriate all other parameters being equal), regional administrations weaken their execution (by an amount that might be appropriate all other parameters being equal), private organizations, from corporations to knitting clubs weaken countermeasures in their procedures (by an amount that might be appropriate all other parameters being equal) and individual weaken both their personal protection habits and their adherence to all those rules, by an amount that might be appropriate all other parameters being equal.
Nobody can revert all those compounding weakenings, the only single point of correcting for them is at the top level: in the second wave, you need considerably stricter government rules to get the same effect. And even they are only corrected in a reactive way, when the numbers become too bad, when the wave becomes too high. Hence the almost universal big second waves.
Not all. At least here in Norway we had about double the confirmed infection rate on 12th November (771) that we had in the early peak on 26th March (423), 7 day averages. We are now down to 110 per 100 k people (14 day average).
But on the 9th March 17% of tests were positive, on the 18th of November it was 3.5%, now it is only 2.2%. But we test a lot more people now; 6k tests per day in the early peak in the spring, 31k in November, now about 90k per week, roughly 1600 per 100k people.
Here the second wave was regarded as rather serious but the threshold for regarding things as bad is rather lower than is usual in Europe; in comparison with most of our peers and neighbours we have it pretty good.
Sources: https://www.vg.no/spesial/2020/corona/#norge, https://www.vg.no/spesial/2020/corona/norden/
"The virus can also spread after infected people sneeze, cough on, or touch surfaces, or objects, such as tables, doorknobs and handrails. Other people may become infected by touching these contaminated surfaces, then touching their eyes, noses or mouths without having cleaned their hands first."
https://www.who.int/emergencies/diseases/novel-coronavirus-2...
I don't think that is a correct conclusion. It doesn't behave linearly.
"We can think of disease patterns as leaning deterministic or stochastic: In the former, an outbreak’s distribution is more linear and predictable; in the latter, randomness plays a much larger role and predictions are hard, if not impossible, to make. In deterministic trajectories, we expect what happened yesterday to give us a good sense of what to expect tomorrow. Stochastic phenomena, however, don’t operate like that—the same inputs don’t always produce the same outputs, and things can tip over quickly from one state to the other."
https://www.theatlantic.com/health/archive/2020/09/k-overloo...
Preventing these imperfections is extremely important in a very high infectivity environment like a hospital's Covid ward, but they don't really change the masks' impact on the epidemiologics of supermarket trips.
A protection level that only shifts the average time to infection of a Covid ward's staff from Monday to Thursday would be terrible, but the same level of protection added to otherwise unprotected supermarket goers can easily reduce the supermarkets' contribution to the R value from heavy to insignificant.
Yes, of you do not impeccably follow the procedures required by medical staff in high infectivity environments the small remaining risk of defense penetration will rise by a high factor, no, the remaining protection will still be much better than no mask.
Based on that data, I can conclude that the measures do show some effect.
The effect is less observable in the "cases" data, where the daily number of cases indeed grew since 7th, but even there there should be a lag of a little less than a week from the point the measures start (it takes time for the people who were infected before measures to incubate and be able to be tested positive or get sick). Interestingly, that is what we see there: there was growth in 7-day average daily cases until Nov 13, then only on Nov 21 that number gets higher again. Which indeed points to the possibility of measures working less from that point on, but at least the growth since Nov 7 is also obviously lower than it was before, which is also what can be expected if the factor that the newer measures bring is low enough that the speed of the spread is reduced, but not high enough to reverse it.
So there are signs that the measures, as much as they are followed, have some effect, but sadly not enough to reverse the trend.
https://www.worldometers.info/coronavirus/country/lithuania/
Slovenia, on another side, has practically the same amount of daily cases for the last 30 days, when 7 day moving average is calculated, but the equvalent calculation of deaths show flattening only between 17th and 26th, and then there's growth of daily deaths again. As the average number of daily deaths is the statistics which is less influenced by the number of tests performed and it's independent on the success of contact tracing, that shows that in Slovenia the spread is still not under control, and additionally, that the month long flattening of the daily cases could mean that there's a bottleneck in health system -- that relatively fixed number of persons could be processed daily, but that due to the priorities those who are processed are, through the time, the patients with worse conditions, resulting in continuous growth of deaths (and the last is just a hypothesis which can be verified or rejected based on the exact related information from Slovenia).
https://www.worldometers.info/coronavirus/country/slovenia/
As for the "announcement effect", I did start wearing a mask when the mandatory mask policy was announced, before it became actually active in the following week. And I wasn't the only one that did that, so some announcement effect is very plausible to me.
Are you implying the measures are to purposefully infect risk groups?
I think mask measures are not working correctly - all the masks are way too dirty - effects are most likely going in the wrong direction.
Getting good data to evaluate measures currently isn't easy. Some curves using "reporting date" look seriously different than curves using "date of death".
NRW is a big region of Germany and still has some good data. The RKI numbers and date of death numbers fit, RKI is lagging only a few days. https://www.lzg.nrw.de/inf_schutz/corona_meldelage/index.htm... https://de.wikipedia.org/wiki/COVID-19-Pandemie_in_Deutschla...
If you look at death 7-day averages NRW has an awful bend upwards - exactly where the new effects of masking/lockdowns should be.
Positive trend-changes of the first mask mandate are non-existent - there's only a small move in the wrong direction (date of death 26.Mai).
Already wrong, the very article shows that Jena had about 145 verified cases in April 6. And test availability was absolute shit in March/April. It still isn't much better now, but from the relation of cases and deaths in the first and current second wave[0], we can infer that current testing is about 3 times that of April.
Actual cases therefore were at least about 450 in April 6, if we generously assume everyone who is positive gets tested right now. Jena only has a population of 110k BTW.
[0] https://www.worldometers.info/coronavirus/country/germany/
https://experience.arcgis.com/experience/478220a4c454480e823...
It bases its conclusion on a few hundred cases in the German city of Jena back in April. In fact, the authors themselves apply the same analysis to other cities over the same time period (figure S15 in the supplementary material) and those plots show hardly any effect.
However... if a paper claims to support X and the paper is bad, then that does not mean that X is incorrect. And given government advice around the world, it seems pretty clear that masks are understood to do more good than harm.
That's an appeal to authority. It also doesn't mean it's incorrect but it's not evidence of anything.
That said, let me double down and state that I wholeheartedly recommend using the scientific consensus as a prior for your opinion on any given topic. :)
Especially in a case such as this an appeal to authority can be useful, as there is a big bad-faith storm of "discussion" surrounding the subject that really isn't doing anyone any favours.
With limited knowledge, I'm inclined to go along with measures that are low cost and have a plausible explanation wrt. effectiveness. That being said, if the mask situation has shown us anything, it's that the authorities are neither trustworthy nor competent.
How did the mask situation show that authorities are not trustworthy or competent?
Otherwise going to a doctor for a sickness, or hiring an engineer to build a house would be fallacious as well.
(And give the amounts of PhDs that are incompetent or just crazy in areas they should know better is astounding but I digress)
Don't trust anyone but yourself.
With that said, the medical professionals telling people to wear masks always say in addition to distancing and hygiene.
1) https://news.ycombinator.com/item?id=25301380
2) The Swiss cheese model of how defences, barriers, and safeguards may be penetrated by an accident trajectory (see the figure):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117770/
https://www.wsj.com/articles/how-the-swiss-cheese-model-can-...
They use a 7-day rolling average and general consensus is that covid has a 3-14 day incubation period. Combining these two would indicate that the mask's effect should be gradually becoming stronger starting ~4days after introducing and reaching peak effect after 21 days in the graph. The graphs show a strong effect after 4 days and remain constant after that. Does that undermine the conclusion or am I seeing this wrong?
They use a linear regression while infection is an exponential process in my understanding, doesn't this undermine the regression?
Jena is a single data point supporting the effectivity of masks (there could be indirect effects at work as well, i.e. people better grasping the severity of the situation). The sophisticated average that they use as comparison makes it appear to carry more confidence than it does.
[1] https://www.corona-in-zahlen.de/landkreise/sk%20weimar/
[2] https://www.corona-in-zahlen.de/landkreise/sk%20jena/
And that is why post-hoc hypotheses aren’t valid. It does not, however, invalidate this study.
Incidentally, I found somebody who prayed for all cities except Weimar and Jena, so this neutralises your anonymous friend’s prayer.
I agree on this. Can you point to where they announced the study on April 6th or before? Or did the decide to look at Jena only after the data was available? How is that not a post-hoc hypothesis?
Of course, both general hypotheses of masks and prayer predate Covid19.
> It does not, however, invalidate this study. No. The study contributes a single data point in favor of masks, but is not very convincing (in that the authors did not look deep into contradictions and alternative explanations) and of course not conclusive as the bad title makes it appear.
You’re right that it’s a single data point (though with a strong effect size). And, being an observational study, it simply can’t exclude all confounding factors, and will never approach the strength that a controlled study could. Nobody is disputing that. Interpretation of observational studies always needs to be tempered by the reality that it’s impossible to control for all confounders.
But within these given constraints the study essentially provides as strong evidence as could reasonably be expected (unless the study has a flaw that I’m overlooking and which, as far as I know, hasn’t yet been pointed out elsewhere). Their design of the synthetic control is statistically sound and controls for a very large number of reasonable confounders. And, contrary to the claim in the comment I’m replying to, data from other cities does not invalidate the study’s findings. As far as I can see, the study’s inadequacies are all due to external circumstances and not because it’s a bad study.
Until sometime in March or April, government advice all around the western world was that masks in community settings are ineffective and possibly dangerous (due to improper handling).
Usually when these agencies change position or announce a new position, the decision is accompanied by a properly referenced whitepaper that lays out the evidence for the new position. This hasn't happened here.
As it happens the UK's second wave kicked into exponential increase around mid August - the only major public health policy intervention coincident with this was mandatory mask wearing. So yeah.
1 - https://www.gov.uk/guidance/get-a-discount-with-the-eat-out-...
Of course this is just my rough calculation (latest population census divided by the number of active cases), and the number is expected to improve somewhat as the amount of population with antibodies increases, but I'm pretty sure masks help.
That’s wrong, the opposite is the case. The study controls for this by looking at a synthetic control over the same time period, which consists of other populations without mandatory mask-wearing. It’s an observational study so it can’t control for everything but it does control for seasonality, even if “seasonality” isn’t specifically mentioned in the paper.
https://www.acpjournals.org/doi/10.7326/M20-6817
But something seemed to change, at least here in Thailand. Although mask wearing was normalized in cities as self-protection against air pollution, many/most people seemed to come around to the notion that mask-wearing was a collective effort to mitigate the spread of the virus. Seems like a cultural effect - more collectivist rather than individualist thinking.
I'd be curious to see if mask wearing Asian countries had less incidence of the flu than western countries.
At least in Denmark I don't think it's communicated very well why you should wear a mask. The government says "wear a mask" so the majority wears a mask. It's great that we have that level of trust in government, but it also sometimes mean that things are communicated as well as they should be.
The fact that places in the world (like Adelaide and Melbourne) even considered lockdown before requiring masks was incredibly lazy and/or negligent.
That’s not what this study says. What the study actually says is that they found wildly huge odds ratios in their confidence interval. The only “conclusion” that can be drawn from this is that the study is inconclusive.
To explain further: to positively conclude that there’s no benefit to mask wearing, the study would have had to produce a small confidence interval around zero effect. In reality, its 95% confidence interval is between 46% reduction to a 23% increase in infection. Any number between these bounds is compatible with the study results. That’s all over the place, and doesn’t allow any conclusion.
If I were that concerned about my own health, I wouldn't be wearing the same unwashed cloth mask for weeks. (I'm vaccinated against a whole bunch of pneumococcus and respiratory diseases)
People are not surgeons. The goal is not to maintain a sterile environment. The masks people generally use are not even rated for that.
The situation is simple. With airborn virus, people will get contaminated when they come into contact with droplets containing virus. Given the typical viral load of people having Covid-19, the issue will mostly be with large droplets. These droplets are stoped by masks. Of course, you are going to emit droplets when you are drinking or eating but far less than than you would have not wearing a mask at all.
The point is not to gain protection. It's to limit your chance of contaminating other people if you are asymptomatic.
[1] https://www.medpagetoday.com/infectiousdisease/covid19/88692
Please explain or link.
https://thefederalist.com/2020/10/29/these-12-graphs-show-ma...
EDIT: I would appreciate a proper rebuttal instead of what I can only interpret as downvotes for wrongthink.
[1] https://en.wikipedia.org/wiki/Gish_gallop
There is no information about what proportion of the populations actually wore masks, how close people actually got to each other, what the population density and degree of urbanization is, etc.
In Norway we mostly have not had strict lockdowns and have not had compulsory mask wearing until very recently and our infection rates and death rates are lower than most other countries as shown on the charts. But you need to be careful how you interpret that; Norway has a relatively low population density and a large proportion of jobs are of a type that can be done at home. So pretty much everyone who could work from home immediately did so (a lot did anyway). We also have a strong tradition of solidarity; unlike the UK 'We're all in this together!' is not just a slogan.
Our government has also been largely consistent in the advice that it has issued and, with a couple of exceptions, avoided overreacting which means that people are willing to adhere to the rules even though most are just advice and not enforceable.
Most charts from all sources, and especially things like the Federalist, should be taken with a shovel of salt; not because of what they include but because of all the information that is omitted.
>There is no information about what proportion of the populations actually wore masks
If you had scrolled a bit, you'd have seen the chart linked highlighting compliance rates: https://yougov.co.uk/topics/international/articles-reports/2...
I looked at the chart titled 'Avoiding going to work' and was bemused because I couldn't see the line for Norway, where I live. When I turned of the Asia, and US I was able to see it. It would be interesting to know the expected error of the surveys that were used to generate that because the impression I have is that vastly more than 18% of the Norwegian working population is working from home. In fact even in normal times a lot of people work from home a significant fraction of the time.
So I am still of the opinion that such charts don't tell us very much and in particular they do not tell us how much we can rely on them.
And one last point: there is a chart showing that 40% of Norwegians say that they are 'Avoiding physical contact with tourists'. What tourists? There have been essentially zero foreign tourists in Norway since March and internal tourism has practically disappeared a well so what meaning, if any, can be associated with such a statistic.
1. The article attacks a straw man, in that it suggests that masks are supposed to be a cure-all against Covid-transmission. I have not heard this seriously claimed - rather, masks are only one of a range of responses. (Indeed, by far the most important and effective reaction seems to be reducing the number of personal contacts - masks are only intended for those situations where this is not possible.)
2. Masks can only be effective where they are worn. At least in Germany, recent data suggests that most infections are taking place in private settings - where masks are not compulsory (and usually not worn). This could be used to argue both ways: either that the widespread use of masks in public has been successful in reducing infections in the public space, or that the continued widespread infection in private settings means that wearing masks in public is irrelevant. (I do not have the data to meaningfully compare these two claims.)
3. The evidence we have on the effectiveness of masks does seem to be pretty patchy, with many studies showing methodological problems and coming to different conclusions.
4. Generally, the protection effect for the wearer seems to be low or non-existent. However, while not significantly reducing inhalation of virus particles, masks do reduce droplet exhalation (and so protect others in the vicinity of the wearer). I.e., there is an indirect protection effect.
5. It seems to be true that masks are not very effective against aerosol infection (preventing this requires other measures, specifically good ventilation). However, this cannot be used to argue that masks are superfluous, as droplet infection (which masks do help with) is another important transmission vector for Sars-CoV-2.
TL;DR Masks are not a cure-all. They must be used in conjunction with other preventative measures, or they are useless. However, they are probably effective as part of such a larger package.
When the situation gets worse then not only the top smartest people but also larger masses begin to take it more seriously to protect themselves, keeping distance, and omitting trips and reducing contacts.
This obviously doesn't apply to careless people or "non-believers" but they wouldn't be much affected by regulations either. So there's always (hopefully) a minority of the population where the virus can spread more easily but once the majority successfully does react it will show positively in the growth curves within about 10 days.
Coincidentally this is also the same time where governments impose strong recommendations or even enforce counter measures. Mandatory shutdowns of cafes and restaurants might seem an effective ordinance but the truth is that by that time most people already refrain from going to crowded places such as cafes and restaurants. And usually there's at least a few points of empirical data from neighbouring countries that those same counter-measures alone won't help limiting the growth if the people themselves aren't in it. It only takes one mask-wearing country to not recover from infection growth in order to make it questionable whether masks help much at all.
Keeping distance seems much more effective than masks. In reality, I've seen that when masks became common place people partially reverted back to flocking together and not respecting a good radius of personal space anymore. Masks probably won't hurt if you need to be close to other people but it would be much, much better to keep the distance in the first place.
> When the situation gets worse then not only the top smartest people but also larger masses begin to take it more seriously to protect themselves, keeping distance, and omitting trips and reducing contacts.
I've noticed this when visiting the shops daily when I get my lunch. Before mask were mandated, almost everyone kept each other at a distance. Since mask wearing people have barely bothered.
I've mentioned this to friends on my discord server. Some are from Europe or elsewhere in the UK and they have noticed the same.
Also it's not only smart people who don't get infected. Think about anyone with kids , anyone doing a job in which they face more people.
Germany did not wear masks on the first shutdown in spring (same as Danmark and Sweden) - the were not available and they came as the spread already went down heading summer.
As for the headline, Germany has a strict shutdown at the moment.
The authors compute a sophisticated average of German cities and compare the weighted number of positive SARS-CoV-2 tests to the city of Jena for a timespan of one month starting just before masks became obligatory there (6th April). Masks did not become obligatory elsewhere and roughly around the mask obligation new positive cases drastically reduced in Jena whereas the weighted average shows no such effect.
EDIT: moved my doubts in the study into extra comment.
If you think the summary is wrong, please leave a comment pointing out in which way, after downvoting.
The study does not look into other east German cities like Weimar[1] or Rostock that showed a similar drop in positive tests without mask obligations. New positive tests in Jena recently reached an all time high. [2]
[1] https://www.corona-in-zahlen.de/landkreise/sk%20weimar/
[2] https://www.corona-in-zahlen.de/landkreise/sk%20jena/
On top of that it seems the study hypotheses for these papers are clearly biased towards proving a positive correlation between infections and mask use, even though one could do exactly the same kind of study in many other parts of the world where infections exploded along with increasingly expansive mask mandates. For example France and Spain, where numbers only started to go down after they went into second lockdown.
No matter what you think of mask effectiveness, cherry picking statistics is bad science, and so far that’s all I’ve seen as far as the ‘masks are effective’ studies go.
I have to challenge this assessment from the article. Masks did become mandatory elsewhere. Mostly in targeted spots in the cities such as the zeil in Frankfurt and Potsdamer platz in Berlin and I can tell you that it is met with strict enforcement and that people are adhering to the rule ardently with very few exceptions. The article and much of the science leaves much to be desired.
It is my opinion that the “all or nothing” pro mask people are actually obstructing the science. Their intolerance to confront or question evidence that is contradictory or unexplained anomalies in the data such as this article is dangerous to actually having the right response to covid leads to nonsensical draconian rules like the California mayor suggesting requiring wearing a mask 24 hours a day and only removing between bites when eating.
[1] https://www.msn.com/de-de/nachrichten/panorama/ab-freitag-ma...
Where are the "if it's not a double blind study where you isolate a variable, you haven't proven anything" people when we need them!
This effect is controlled for by the study, by comparing Jena to synthetic control groups.
Yes if only we had a second Earth.
I feel like every other day there is a new study or report that refutes the study or the report I just saw from another respected institution. I'm not surprised people are frustrated at this problem. As an example, look at this study that was posted just 13 days ago on HackerNews: https://news.ycombinator.com/item?id=25159583
The Danish study is not good. They're not controlling for mask/no mask, they're controlling for suggestion to use masks (and they didn't even go back and ask "did you wear a mask or not).
In the end it seems people are more worried in publishing hastly prepared experiments/results than worrying about getting to the bottom of things.
> How can we not know based on the shear mechanics of these two entities whether this is effective?
It seems obvious to me that masks have a positive effect. A mechanical barrier is better than nothing. "Oh but influenza" Influenza and Coronaviruses are different
Doctors and Dentists don't use masks because they think it's funny or comfortable
Especially when tongue depression or other procedures might trigger a release of saliva, or make the saliva in the mouth spread. Or cough. Or sneezes.
If you were a doctor, would you be happy seeing a patient with a weird cough without masks/eye protection?
"The results could indicate a more moderate degree of protection of 15-20%" to the wearer.
"The findings are consistent with previous research. Health experts have long said a mask provides only limited protection for the person wearing it, but can dramatically reduce the risk to others if the wearer is infected, even when showing no symptoms. Preventing the spread to others is known as source control."
Now consider the following: if the "current" R number (the average of how many people are further infected by one infected person) in some environment is 1.2 that still results in the number of infected per day exponentially(!) increasing. Example: after the sequence of 10 infections with R 1.2 there are 6 infected, after the sequence of 20 -- 38, after the sequence of 30 -- 237 and after the sequence of 100 -- 82 million people infected, starting from just one. It is estimated that it takes just a few days for one sequence. Taking that number to be around 3.6 (it doesn't have to be that number, it's just to take some convenient number as an illustration) means that 100 sequences can be imagined as one year. So 82 million in one year.
Now if every wearer is protected only 20%, it can appear to the wearer who doesn't understand math that he should not wear it. However, reducing current R number from 1.2 to 1 means that the number of infected per day doesn't increase at all but remains constant. Example: starting with 1 infected, after the sequence of 100 there are just 100 infected. Using the same convenient number, after one year, still just 100 infected.
That, in turn, means that if everybody wears it, everybody wins: allowing exponential increase of infected will result in everybody becoming infected, whereas the constant number of daily infected could guarantee that most don't become infected before they can be vaccinated.
Not to mention that if the number of infected per day can be kept constant some other kinds of measures (lockdowns with closures, bad for economy) could be completely avoided, especially if it is achieved at some low level. Which means that it can be of immense benefit to the wearer to wear the mask as much as possible even if he increased his own direct protection in some specific situation for mere 20%! Moreover, the benefits are dependent on most others also wearing the mask! If he's doing that alone, than it's in vain -- he alone can't change R for the whole population: his highest interest is to convince others to do the same.
Being willing to understand math and to read carefully helps.
Side note, I recently read a good book that addressed why people have such a hard time with percentages. People tend to take numbers like 20% and think 0 and 80% and think certainty.
https://www.albartlett.org/presentations/arithmetic_populati...
"It's a great pleasure to be here, and to have a chance just to share with you some very simple ideas about the problems we're facing. Some of these problems are local, some are national, some are global.
They're all tied together. They're tied together by arithmetic, and the arithmetic isn't very difficult. What I hope to do is, I hope to be able to convince you that the greatest shortcoming of the human race is our inability to understand the exponential function."
That's why when some hear that R=1.2 can be catastrophic and R=1 can be fine they just switch off. And there is exactly that "only 20% percent" difference.
But many developments in nature that work against humans have exponential behavior, including the stuff that humans do.
Somebody once named the video of that Bartlett's presentation "The Most Important Video You'll Ever See" and in this case it's not a clickbait.
Edit: What's the name of the book you mention?
1) https://news.ycombinator.com/item?id=22655785
Yes yes, I know. Just let me explain.
Masks DO help prevent the range particles can travel when you breathe. I'm not arguing that. The fact is, however, they're useless in comparison to the ACTUAL champions of prevention.
And that would largely be hygiene. I'm willing to bet 99% of you reading this do not clean your fingernails properly while washing your hands. Which is fine, THAT'S how good soap is. Doing it poorly is orders of magnitude better than not doing it all.
Is the same true of masks? Absolutely not. If you don't wear a mask properly, it's useless. It gets worse with specialised gear, like the N95s. You need to be trained on how to fit, test and adjust that. Have a beard? Not gonna work. Small leak out the top? Nope, it's buggered.
You ever notice how developing nations struggle with higher infant mortality rates, caused by preventable communicative diseases like cholera? It's because they don't wash their hands with soap. Soap is literally a life saver [0]. There's a damned good chance it's saved you a nasty infection, if not your life, directly or otherwise.
It's strange to me we understand why gloves aren't effective, but somehow that logic gets lost when masks pop up. If you don't know how to stop yourself from contaminating your environment, you're really not getting anything from wearing a mask. Or gloves. Or scrubs.
China is a fantastic example of this. They just ignored the whole "human rights" problem and went straight to welding people into their own homes [1]. Highly effective. Conversely, they'd been wearing masks for a long time because of their air pollution. Clearly not very effective. (The point here is the behavior and the objective is more important than the mask).
Here's what we should be focusing our energy on:
1. Social Distancing
2. Wash your hands properly [2]
3. Coughing etiquette
4. And then, finally, PPE including masks. If you don't know how to use gloves properly, then don't waste your money (because we all seem to forget economics is also a problem to solve here).
JUST focusing on masks won't cut it. Rather focus on JUST washing your hands then. You will see a much larger return on investment there. That evidence is also irrefutable. Compare the rate of death from communicable diseases in areas where washing with soap is prevalent to areas where it is not. SARS-CoV-2 has a lipid bi-layer, so soap will destroy it.
[0]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2587156/
[1]: https://www.cbc.ca/player/play/1703503427818
[2]: https://www.youtube.com/watch?v=xLIFT9xoWSQ the key bit here is scrape your nails against your hands when they're full of soap, so that the soap gets UNDER your nails too. Germs are tiny, and everywhere. So get em good
And as for coughing etiquette, I can’t remember when I last heard somebody cough or sneeze when out. I’m sure it happens (after all, it’s sometimes unavoidable) but it has definitely gotten much rarer. In sum, it’s a very strong claim to say that “masks are a pointless waste of time”, and almost certainly wildly off the mark.
^1 Of course hand-washing should be practiced nevertheless, because it also prevents other infections, notably GI infections. But paradoxically excessive hand-washing also has negative health implications: soap and alcohol destroy the skin’s protective layer and dry it out, and the mechanical action of hand-washing exacerbates this through abrasion, which causes micro-lesions, irritation, and increases the risk of catching infections. And unlike for mask-wearing we actually have very good evidence for this. We don’t yet know the exact consequences, but the NHS has noticed a strong uptick in dermatological conditions since the beginning of the pandemic, some of which are serious. (Here’s a publication on this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102542/)