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lukev · 5 years ago
I don't understand why people feel the need to say stuff like this. It's dangerous and wrong.

Yes, sure, masks are ineffective if you define "effective" as "a complete barrier to infection". Congratulations, you've successfully unmasked the the grand mask conspiracy.

Except that definition is next to useless. What masks do do is reduce the amount of aerosolized particles that are emitted and inhaled. It's not meant to be a protective barrier, it's meant to be a numbers game.

Saying masks are useless is like saying you can catch Covid from your mailman, so if you accept mail packages you may as well just go to a concert.

It's all about volume and probability of contact.

I'd also be interested to hear someone with more knowledge of the science weigh in on the studies he cites. If masks are as completely useless as he claims, I would expect the (already high) infection rate among medical providers to be even higher, at 100%. What gives?

DanBC · 5 years ago
People make two claims for masks.

1) They prevent the wearer from getting the virus from other people.

2) The prevent the wearer giving the virus to other people.

People talk a lot about viral load, and about breathing droplets deep into your lungs. So, (2) doesn't make much sense to me. The person with mild covid-19 infection places a mask around their mouth and nose, thus trapping all those infected droplets, which then get breathed back in. If the mechanism of action really is "breathing the virus causes severe infection" why would you want to trap the virus by your mouth and nose?

> If masks are as completely useless as he claims

They're not saying they're completely useless. They're saying that lots of the people wearing masks expect 100% protection, even if they're doing fucking stupid things. There's absolutely no point in both wearing a mask and going to a football match. https://www.thenational.ae/image/policy:1.998514:1585469410/...

If we're going to force people to wear masks we need to make sure they're wearing them correctly, because an incorrectly worn mask may do more harm than good.

bootlooped · 5 years ago
The first linked study, the one from Japan, had 32 participants that finished the study and there were only 2 colds observed, one in each group. To me, a layperson, that feels like such a small sample size to be totally useless. Am I wrong about this?

It's also stated, "The main transmission path is long-residence-time aerosol particles (< 2.5 μm), which are too fine to be blocked". Why when I look at a CDC article on masks does it say N95 is effective on this particle size? Unless the author is using "blocked" to mean "100% prevented from moving through the filter", which would be a higher standard than N95 masks claim to have.

https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/

zzzcpan · 5 years ago
Both surgical masks and N95 masks can filter out 2.5 μm particles coming in, the author even cites research showing no difference between them, but it's a trolling piece, not a scientific paper. The author claims a lot of ridiculous things.
JPKab · 5 years ago
Jeremy Howard (of FastAI) is doing a major metastudy on masks at the moment. Pretty sure they work.
magduf · 5 years ago
Correlation doesn't guarantee causation, but the Asian countries where mask-wearing has been commonplace for a long time have done far, far, far better with this pandemic than nations where no one wears masks in public.
zinclozenge · 5 years ago
> Correlation doesn't guarantee causation

This is a vacuous statement in this context and adds nothing to the discussion, because you can never prove causation via a study/experiment, only reject the null hypothesis.

throwaway743 · 5 years ago
If the neuroinvasion of SARS-CoV-2 does take a part in the development of respiratory failure in COVID-19 patients, the precaution with masks will absolutely be the most effective measure to protect against the possible entry of the virus into the CNS.

Can be found in the document under "Supporting Information" at the following address:

https://onlinelibrary.wiley.com/doi/full/10.1002/jmv.25728

DanBC · 5 years ago
I've been fairly strongly anti-mask. I'm not sure the linked paper is persuasive.

I prefer the papers mentioned here (which argue against my anti-mask position and are changing my mind a bit): https://www.fast.ai/2020/04/13/masks-summary/

Zenbit_UX · 5 years ago
Hey doctors in ICUs right now, masks off! You heard it here first folks, a study says masks are pointless despite all common sense and decades of usage in hospital settings.

Anyone want to take bets before this information is tweeted out by potus and on infowars?

cbm-vic-20 · 5 years ago
Masks tell me who is taking this thing seriously, and who might not be.
skat20phys · 5 years ago
In what direction? I think part of the point of this paper is that most masks aren't taking things seriously enough.
magduf · 5 years ago
No, the point of this paper is that masks are not completely, absolutely, perfectly, 100% effective and foolproof, and therefore we shouldn't use them at all.

I really have to wonder if the people pushing this have some kind of agenda.

teknico · 5 years ago
Is this accurate?
elmerfud · 5 years ago
I can't comment if his paper is accurate without investigation of all the citations. In general masks are meant to stop larger particulates than what viruses are, that includes the n95 masks. Also medical masks and shields are intended to protect the wearer more than they are too prevent the wearer from spreading their infection. Breathing out puts positive pressure behind the mask causing it to bypass any filtering effect of the mask.

Cloth masks are a complete joke as far as preventing spread unless you're someone who constantly sprays spittle when they talk. If you are that person then no one wants to be in spray range already . Cloth masks will barely filter dust out. The anecdotal story I share about the masks being more about a social construct than a medical one is this. My wife works in reception at a medical office. They started requiring all staff to wear makes but those in non-paitent facing roles (like her) only get cloth masks. They acknowledged that the cloth masks did nothing to prevent the spread but it was important to make masks socially acceptable.

The papers closing does seem to have the conspiracy angle to it which I can't comment on if this is the case or not but overall there does seem to be quite a bit of "virology theater" going on with policy making.

d1str0 · 5 years ago
Cloth masks can definitely help though. They are good at one thing in particular, reducing spread and velocity of air movement from your face. If you breath, cough, or sneeze, the transmission distance is highly reduced. You still have virus escaping, but it cannot travel as far.
Zenbit_UX · 5 years ago
A distinction needs to be made between what I suspect you mean when you say a "cloth mask" which is likely the equivalent of wrapping a t-shirt around your face and a pocketed cloth mask which acts as a frame for a hepa filter.

I've made two hepa cloth masks using online guides (I know, I'm like an expert now /s) for my partner and I and from my testing they filter out a non-trivial amount of undesirable particles. We use a pipe cleaner to add rigidity to the upper mask and form a better seal. I've lit a cigarette right in front of my mask and been completely unable to smell it. Does this offer us 100% protection? No of course not, is it better than not wearing one? Yes, of course.

skat20phys · 5 years ago
My sense of the literature is that it's accurate in the limited sense that masks often don't have statistically significant effects in studies. It's maybe also accurate in the sense that the effects of masks are really being overrated, even many n95 masks.

However, in many studies there's a consistent trend toward masks doing something, in the sense that measures of dispersion are attenuated with masks vs not.

This paper is pretty poor in that it commits the classic statistical blunder of equating multiple nonsignificant results with overall effect size. It's very hastily put together.

One of the meta-analyses cited is an example of some of these issues (Offeddu, V. et al. 2017). You can see there's few studies and the ones included result in a nonsignificant effect, but it's almost significant and in the intuitively expected direction (PPE having an effect). But then there's issue of publication biases etc.

My general impression is that the truth is somewhere in between, maybe closer to what this essay is arguing in the sense that masks are much less effective than people think, but probably not actually technically correct in that masks probably have some effect.