
Masks really work to reduce the spread of Covid-19 - nopinsight
https://twitter.com/jeremyphoward/status/1242894378441506816
======
remarkEon
This whole argument is frustrating and annoying to me. I know that we're
obsessed with "data" and "increase the sample size" on this website, but those
things take a lot of time. And, given that my parents are old and have at
least one factor that make them "high risk", I've started to reevaluate my
priors on constantly insisting on more and more data before I make a decision.

Taiwan, Japan, Singapore, Hong Kong ... they all wear masks to some extent,
normally in non-pandemic periods. They now do it at scale. They're at the
bottom of the barrel in cases today (Russia is too and I don't really
understand why unless they're lying). So, perhaps we should just start wearing
masks. It costs nothing, assuming it's possible to get them, though for
whatever reason our smartest people - both in the actual elite and here on HN
- exclaimed that wearing a mask "does nothing". And one of the results of
everyone telling us back in January and February that "masks do nothing" is
that we're now 2 months behind procuring a cheap item that could actually do a
lot of good. What a damn shame.

~~~
bibabaloo
> our smartest people - both in the actual elite and here on HN - exclaimed
> that wearing a mask "does nothing".

I'm fairly convinced that the messaging behind the "masks don't do anything"
rhetoric is to prevent a shortage to people who need them. Yeah, everyone
wearing masks would probably effectively slow the virus but if there's known
supply chain issues and everyone stocking up would cause availability issues
for doctors & nurses, then we have to take the lesser evil.

~~~
FeepingCreature
Yeah but the _effect_ is a diminished trust in experts. Which is why noble
lies are toxic. Like, nobody who said that masks can't help has grounds to
complain about accusations of "fake news" ever again.

~~~
joaomacp
People's decisions today are so influenced by media that fake news become
acceptable (like white lies).

Media has to act as the Catholic Church did in ancient times. It has to make
up some stories to control people's behavior.

Toilet paper is an example of this: you talk about a shortage, and people will
buy more. They don't believe it's really necessary, but since they know other
people are buying and the media is talking about it, even smart people
understand demand will increase and stocks will fall, so they buy more.

Same with masks: if you tell people "they work, but don't buy them" it will
have the exact opposite effect.

In China and other Eastern countries, this is dealt with by causing fear in
people: "if I buy a lot of masks and the state finds out, I'll be in trouble".

We don't have that tool in free Western countries. So media manipulation
becomes the only effective tool for behavior control.

------
wonnage
Like many others, I started off skeptical about masks due to public health
messaging and all the general caveats about how hard it is to wear a
respirator correctly. That’s no longer the case.

Wearing a mask of any sort reduces the risk of infection. That’s why hospitals
need PPE and are even resorting to using lower-grade protection (e.g surgical
masks instead of n95) due to lack of supplies. CDC is even recommending
scarves as a last resort. They’re also reusing masks and wearing them for
longer than they should. These are all signs that _any_ mask can provide some
benefit.

Furthermore, it’s been well cited that wearing masks does more to protect
others from the wearer than vice versa. Given that its possible to be an
asymptomatic carrier, you should wear a mask to avoid spreading the virus
unknowingly.

Obviously, full PPE should go to healthcare and other critical needs right now
due to shortage. That doesn’t mean the rest of us shouldn’t wear masks, just
that we shouldn’t selfishly hoard a bunch of n95s. I’ll bet lots of
Californians have leftover masks from the wildfires that they could use.

My take is that reserving proper PPE for health workers until the crisis peaks
is critical. But westerners don’t have a mask-wearing culture like Asian
countries, and are more likely to have an all or nothing approach to wearing
one (n95 or bust!). So the safest public health messaging is to discourage all
mask wearing. Not sure that’s worked.

------
nopinsight
Taiwan rapidly built up factories to make 10 million masks _a day_ for its
citizens (population: <24 million) as part of its plan.

Masks for everyone in public is a necessary but not sufficient condition.
Check out Taiwan's Covid-19 Response Plan published in JAMA for details:

[https://jamanetwork.com/journals/jama/fullarticle/2762689?gu...](https://jamanetwork.com/journals/jama/fullarticle/2762689?guestAccessKey=2a3c6994-9e10-4a0b-9f32-cc2fb55b61a5)

What is the cost of an automated mask making machine? < $100,000/set (based on
Alibaba data). Each set can make ~100 pieces/min * 60 min * 17 hours > 100,000
/ day.

To make a mask _daily_ for everyone in the US would take 3,300 such machines *
$0.1 million = $330 million.

Along with all other costs, total capital investment is likely less than a few
billion dollars. Costs of capital, materials, operations, and distribution all
together would be negligible relative to savings in healthcare, not to mention
less misery all around.

~~~
MikeAmelung
If we don't take some sort of action to bring essential manufacturing,
including pharmaceuticals, back to the US after this, I might entirely lose my
mind.

It shouldn't matter where you fall on the political spectrum, or if it's going
to cost too much for the labor, or the fact that the whole thing has to be
powered by reverse carbon collection or whatever the hell, it just HAS to be
done.

~~~
scruple
And we should also be losing our minds if our government doesn't go back to
peacetime national stockpiling.

------
Zanni
My sister, a practicing MD, says that cloth masks are _worse_ than nothing
because they act as disease reservoirs. N95 masks are single-use. People
aren't throwing their homemade masks after every trip outdoors, so any
contamination their masks "stopped" is just waiting for the next use to infect
the wearer. (She cited a study she'd read, which I can't find, but this
Wirecutter article [1] makes a similar argument in the first answer).

That said, that doesn't mean that masks aren't helping in Czechia--they're a
potent reminder to everyone to keep their distance, and that their friends and
neighbors have bought into the seriousness of the threat. That alone is worth
something.

1\. [https://thewirecutter.com/blog/your-coronavirus-questions-
an...](https://thewirecutter.com/blog/your-coronavirus-questions-answered/)

~~~
jfnixon
I think the wrong model is the problem. Surgical masks provide small
protection to you, but significant protection to others. It isn't for you, it
is for everyone else. Think of a mask as portable social distancing.

By catching droplets from (asymptomatic) infected wearers, it reduces the
virus on surfaces and in the air. That's the benefit.

------
jeffdavis
Does it really matter if it's N95 or would a bandana work? It would make it
harder for a cough to spread from you, for sure. And it would remind you not
to touch your face and keep droplets away from your nose.

Maybe the message should be: healthcare workers get the real masks, but the
public still needs a covering (bandana or whatever)?

------
irrational
Except now there is a serious social stigma against wearing masks. You are
seen as taking what rightfully belongs to the hospitals and using it for your
own selfish ends.

~~~
skybrian
That sounds like a good reason to wear an obviously homemade mask?

------
stickfigure
Scott Alexander of Slate Star Codex just recently posted a review of evidence
on the efficacy of masks, in his usual "I just want to follow the evidence as
honestly as possible" kind of way:

"Face Masks: Much More Than You Wanted To Know"

[https://slatestarcodex.com/2020/03/23/face-masks-much-
more-t...](https://slatestarcodex.com/2020/03/23/face-masks-much-more-than-
you-wanted-to-know/)

------
zenexer
I’ve been seeing a lot of social media posts from friends and family who are
wearing masks incorrectly or making their own masks. That might not be a huge
problem on its own, but it seems to give them an excuse to risk compensate.
And that’s a huge problem.

If you plop on an N95 mask, it’s not going to work as intended. Sure, it might
block some stuff and discourage you from touching your face, but it’s
certainly not going to make you invincible. Even when fitted correctly, it’s
still letting stuff through. If you have to choose between staying home vs.
gathering in a group while wearing a mask, one is obviously lower risk than
the other.

N95 masks are uncomfortable. When used correctly, you feel like you’re
breathing hot, humid air that you just exhaled. They clamp down pretty tightly
on your nose.

People don’t like this, so they adjust the mask until it’s comfortable (or
just don’t fit it in the first place)—and in this case, comfort = leak. Or
they get a mask with an exhaust vent—which might protect the wearer reasonably
well, but now everything they exhale exits the mask unfiltered. Or—and this is
my favorite one—they put the mask on over sunglasses to keep it from sitting
on the bridge of their nose, then wonder why their glasses fog up.

Or perhaps they have facial hair that they don’t want to shave. For the seal
to work, the part making contact with your face needs to be clean-shaven.

And you can’t make your own N95 mask from scratch. They’re not simple cloth;
that’s why they’re expensive and hard to produce.

Again, none of this would be terrible if people didn’t risk compensate.
Wearing any mask—even incorrectly—is probably better than no mask, as long as
you didn’t cut up a fiberglass HEPA filter in the process. Wearing a mask to
get some groceries or pick up a prescription? Great! At the very least, it’ll
keep you from touching your face. But wearing a mask so you can throw a party
is a terrible idea.

I’m mostly targeting N95 masks here since they’re not as easy to use as
surgical masks, but the same general rule applies to everything: masks are an
extra tool in your arsenal; another layer of protection. They don’t make you
invincible.

------
Yuioup
For all you idiots who downvoted me:

[https://edition.cnn.com/2020/03/30/world/coronavirus-who-
mas...](https://edition.cnn.com/2020/03/30/world/coronavirus-who-masks-
recommendation-trnd/index.html)

------
noizejoy
I’ve never stopped wondering if “masks don’t help” messages were given to the
public because there aren’t enough masks for the health care workers (and
others in helping jobs). I really hope not, because if that turns out to be
deliberately misleading messaging, the short term benefit may very well be
outweighed by serious long term trust deterioration in public officials,
beyond what’s already there.

~~~
fleetingmoments
Not to go full on conspiracy theory here but a contributing factor could be
that those in charge don't want wearing a mask in public to become a norm
because it would interfere with facial recognition and tracking.

------
mamurphy
The first four comments when I got here were disparaging this tweet chain and
saying masks don't work. I did a bit of research and found multiple articles
claiming masks DO work.

These sources acknowledge that masks are a contentious point and that some
experts disagree with the part of the articles I am quoting below. Even the
CDC recommends against members of the public using respirators without
specific risk factors (having Covid, or treating someone with Covid). The CDC
wants to prevent hoarding, as they should.

But many sources claim that a homemade mask from a spare vacuum bag or dish
rag makes you a bit safer (2-5x safer than nothing), and I'm going to make one
for myself and use it when going out. From the overall body of evidence, I
believe that masks are substantially better than nothing, and a social norm of
everyone wearing masks would lower Covid transmission. If you disagree provide
sources and reasons.

>Wearing a face mask is certainly not an iron-clad guarantee that you won’t
get sick – viruses can also transmit through the eyes and tiny viral
particles, known as aerosols, can penetrate masks. However, masks are
effective at capturing droplets, which is a main transmission route of
coronavirus, and some studies have estimated a roughly fivefold protection
versus no barrier alone (although others have found lower levels of
effectiveness).[0]

>The public doesn't need to wear heavy-duty respirators, but it's a smart idea
to don a face mask or wrap a clean scarf around your nose and mouth if you're
going into a crowded place during the COVID-19 outbreak, an infectious disease
doctor told Live Science.[1]

Even the CDC agrees that "The role of facemasks is for patient source control,
to prevent contamination of the surrounding area when a person coughs or
sneezes. Patients with confirmed or suspected COVID-19 should wear a facemask
until they are isolated in a hospital or at home. The patient does not need to
wear a facemask while isolated." [2]

Other articles agree that sick people wearing face masks helps prevent them
spreading to others, e.g., [3]

I have read sources that Covid19 can be transmitted even if you have no
symptoms. So if everyone wears face masks, then everyone who is infected with
no symptoms will have a reduced chance of transmitting the virus. Unlike
social distancing and lockdowns, masks have almost no downside. Why are we not
heavily promoting masks for anyone going out of the home!?

HN generally loves the NYTimes, great article: [4]. Homemade masks aren't
perfect, but the article explains that "of course masks work — maybe not
perfectly and not all to the same degree, but they provide some protection.
Their use has always been advised as part of the standard response to being
around infected people, especially for people who may be vulnerable."

I encourage everyone reading this to consider making a mask out of an item you
already own and wearing it when leaving the house.

[0] [https://www.theguardian.com/world/2020/mar/23/can-a-face-
mas...](https://www.theguardian.com/world/2020/mar/23/can-a-face-mask-protect-
me-from-coronavirus-covid-19-myths-busted)

[1][https://www.livescience.com/coronavirus-do-face-masks-
work.h...](https://www.livescience.com/coronavirus-do-face-masks-work.html)

[2][https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-
use...](https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html)

[3][https://www.cedars-sinai.org/newsroom/covid-19-for-most-
mask...](https://www.cedars-sinai.org/newsroom/covid-19-for-most-masks-give-
little-to-no-protection/)

[4][https://www.nytimes.com/2020/03/17/opinion/coronavirus-
face-...](https://www.nytimes.com/2020/03/17/opinion/coronavirus-face-
masks.html)

------
stunt
It's not scalable even if it does help.

Not to mention the whole scams around it these days and ridiculous high price
tags. I'm not surprised if all of these are coming from people that are making
money out of it right now.

------
acje
I have heard from nurse with specialization in contamination that wearing
masks are worse than nothing because we would handle them wrong. That is
touching the mask to speak, multiple use and the like. They don’t do that in
hospitals. You put it on and throw it away only touching the strings. Like it
was contaminated, because it is, if it worked..

I do however see one way masks would work. They act as a constant visual
reminder to keep distance and not touching stuff. That works.

------
Polylactic_acid
If you ever get to the end of your tweet character limit and still need to
continue, that's an indicator that its time to delete your tweet and post it
on a real blogging service and then you can post the link back to twitter if
you want.

~~~
buzzerbetrayed
While you’re obviously entitled to your opinion, many, many people disagree
with you.

------
ykevinator
So why didnt we just distribute masks?

~~~
notacoward
Priorities. It's great to say everyone should use masks, they do help somewhat
even if they're not perfect, but supply was too limited. It's getting better,
but health-care professionals are _still_ having to wear PPE too long or reuse
it or go without. They're terrified, and not without reason; a lot of them
have already been infected. We need to prioritize getting enough masks to
them, then to other vulnerable people, and _finally_ to the general populace.

Compare it to a different kind of mask in a different kind of war - the kind
that one would use to protect against chemical-warfare agents. Or doses of
antidote. Sure, everyone would be safer if they had these things, but if there
are fewer of them than there are people then by what reasoning should they
_not_ go first to those on the front lines? It's a simple effect-maximization
problem, with a solution that benefits even those who don't get the gear.

------
jshevek
I'm not a huge fan of HN links to tweet threads, but if they are going to
happen then here is a far more readable format of the above tweet thread:

[https://threadreaderapp.com/thread/1242894378441506816.html](https://threadreaderapp.com/thread/1242894378441506816.html)

------
modzu
the twitter meta analysis

