The initial recommendation, the flip-flop, and attempts to explain it away have been universally incoherent, because the real reason is that the CDC and FDA combine the worst of the federal government's bureaucratic inefficiency with medical culture's innumeracy and blind status quo bias.
Leaving aside the failures of pandemic preparedness stretching back multiple administrations (the PPE stockpile had been depleted since 2013, and I don't need to describe the trump admin's failures..), it would have been trivial to do what we eventually did, and what many other countries did: recommend face coverings of any sort, and encourage people to save n95s for medical personnel. The insane route we ended up taking had people hoarding n95s anyway and deeply poisoned the well of trust in public health authorities in general and masks in particular (helped along by our president).
2. Most epidemiologists it the US, at least, believed that corona- and similar viruses were transmitted by larger droplets generated by coughing or sneezing. These droplets would not remain airborne long, resulting in the advice for social distancing and surface cleaning. The "flip-flop" occurred very shortly after it was demonstrated that they were transmitted by aerosol particles.
3. This event primarily demonstrates the difficulty of communicating science---a "this is the best advice we can give now based on our limited understanding" is treated as permanent, universal truth by the general public; any later changes in that advice is "insane" and "deeply poisons the well" of trust.
This is both false and doesn't make any sense.
1) There was ample evidence of the distinct _possibility_ of airborne transmission, certainly by March. Medical culture has a severe problem with confusing "absence of evidence" and "evidence of absence", and the cost-benefit tradeoff of mask recommendations given what we knew back then was crystal-clear (and there were people loudly and consistently saying so throughout).
2) The CDC and Surgeon General (of "Seriously people, STOP BUYING MASKS" fame) have claimed[1] that the "flip-flop" was due to a change in concern about asymptomatic spread. It's not a coincidence that this is the _third_ distinct (and often mutually-contradictory!) excuse I've heard on this thread: because the real reason is basically down to systemic cultural rot in the field (especially at a scale that large and politically-influenced) and no one wants to admit that.
> 3. This event primarily demonstrates the difficulty of communicating science---a "this is the best advice we can give now based on our limited understanding" is treated as permanent, universal truth by the general public; any later changes in that advice is "insane" and "deeply poisons the well" of trust.
Scientific consensus changes all the time, and no stigma is (or should be) associated the work on the earlier, less accurate model. That's just what science _is_. I'm not sure if you're being intentionally obtuse or accidentally so, but my point is obviously that the initial no-masks assessment was insane, and based on a shoddy interpretation of both the science of the virus and the fundamentals of how public policy works.
[1] https://www.axios.com/surgeon-general-reversal-face-mask85e2... .
The medical culture also has a bit of a problem with crying wolf---the community has to take care not to do so because randomly changing things can easily cause more damage than it prevents. In particular, the community tends to want to avoid prescribing major behavioral changes without good reason.
Do you remember, say, roughly this time last year here on HN? Hydroxychloroquine was the biggest topic in any COVID discussion. And "why aren't the stupid, rotted, insane medical community providing a cheap, known-safe medication as a prophylactic to everyone?" was the question everyone here was asking. After all, there was the distinct possibility that it could help.
Turns out that the supply was constrained, that it has side-effects, and that it doesn't work. Yay for the medical community, right? Everyone celebrating the success of science? Apparently not: "Medical culture has a severe problem with confusing 'absence of evidence' and 'evidence of absence', and the cost-benefit tradeoff...." But as soon as the ongoing, large-scale trials started dropping hydroxychloroquine from their protocols, the issue disappeared, with no admission that anyone had been wrong.
You are absolutely right that "scientific consensus changes all the time, and no stigma is (or should be) associated the work on the earlier, less accurate model." And yet it does: their earlier assessment is "insane"; it represents "systemic cultural rot".
Your Axios link gives me a 404; do you mean "Surgeon general defends reversal on face mask policy (12 Jul 2020)" (https://www.axios.com/surgeon-general-reversal-face-mask-d38...) or possibly "Where the science stands on using face masks against coronavirus (25 Jun 2020)" (https://www.axios.com/coronavirus-face-mask-science-e9df446b...). The latter article points to:
"Assessment of Fabric Masks as Alternatives to Standard Surgical Masks in Terms of Particle Filtration Efficiency (17 April 2020)" (https://www.medrxiv.org/content/10.1101/2020.04.17.20069567v...)
"Association of country-wide coronavirus mortality with demographics, testing, lockdowns, and public wearing of masks (Update June 15, 2020)" (https://www.researchgate.net/publication/342198360_Associati...)
"CDC to make updated recommendation on masks (22 Jun 2020)" (https://www.wwlp.com/news/health/coronavirus/cdc-to-make-upd...)
"Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis (27 Jun 2020)" (https://www.thelancet.com/journals/lancet/article/PIIS0140-6...)
"Community Use Of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US (August 2020)" (https://www.healthaffairs.org/doi/pdf/10.1377/hlthaff.2020.0...)
That is (a) exactly what I am saying, and (b) actually a little later than I can date the change---I've previously seen (and posted, IIRC) scientific discussion in mid-April to May about the changing consensus on transmission and mask effectiveness.
When you write "it's not a coincidence that this is the _third_ distinct (and often mutually-contradictory!) excuse I've heard on this thread", you do realize that there are multiple people involved in this thread and that some of them are simply wrong. But of course I would be saying that because I'm just making excuses and covering up rot, trying to cover up that everyone except the genii software engineers here on YN are complete idiots.
That makes even less sense, masks only stop the heavier droplets. The virus is small enough to go right through cloth masks when aerosols, or get carried out the sides of surgical marks by your breath.
But I remember the aerosol realization happening around summer/fall last year, way after the mask flip-flop anyway.
As aerosols you need an N95 mask to actually filter them out:
* The virus is small enough that they go right through regular cloth masks; the theory on these was that the cloth masks would catch the too-large-to-pass-through droplets and the virus would get stuck inside the droplet.
* Aerosols are as light as and easily carried by the air, which is why they hang in the air for a long period. Because they're so easily carried by the air, any mask that your breath can escape the sides of, such as a surgical mask, will carry the aerosolized virus out the sides without catching it. It's the same phenomena that stops butterflies from hitting car windows [0]. The larger droplets are like the denser bugs that aren't carried safely away by the air, those will get caught by these masks.
Really, ventilation is the best way to deal with aerosols. Open a window and get them out of the room entirely.
[0] https://physics.stackexchange.com/questions/631854/how-can-a...
I noted this at the time as well, but I read it (perhaps between the lines a bit) as more like: masks probably help, but if you all go panic-buy masks like you do TP, there will be none left for healthcare workers, who need them more than you do.
Note that even if your theory is correct, it also means that public health authorities have been continually lying to us after their mask flip-flop, with the Surgeon General claiming in April that it's because they didn't know asymptomatic transmission was possible. This is, of course, horseshit, as there were Chinese reports of asymptomatic transmission as early as January.
The only theory which fits all the evidence is the one I laid out: asymptomatic transmission did not have a solid, high-quality study behind it yet, and medical culture has serious problems doing anything but rounding priors and weak evidence down to "zero evidence" instead of doing the difficult work of choosing the best option under uncertainty. It's ludicrous to claim that telling people to put scarves over their face would deplete , and that this cost-benefit suddenly flipped the moment the level of evidence for mask efficacy rose from "no-brainer if you're capable of modeling uncertainty" to "has a specific high-quality study supporting it in narrow conditions".
Yup. See also how long it took before the medical community came around to accepting that it's an airborne virus, despite very early evidence from China and South Korea to that effect.
Isn't it simple statistics? If you're on a ward with 10 people who are ill and coughing at you you'll need a mask. If you're walking about in the street, not getting closer than 2m to anyone, and not spending much time in close proximity to anyone, the mask isn't doing much.
I addressed this in my comment:
> Higher viral loads [and longer exposure] put you at higher risk, but the messaging decidedly wasn't that masks are only protective at high viral loads. Let alone the incredibly basic prior on respiratory diseases' vector being limited by _covering up the sources of spread_.
"Medical workers need masks more because they have more exposure" is not the same thing as "masks don't work for the general public", and brazenly and badly lying to the public has costs that have been demonstrable throughout the pandemic (helped along by our dear insane President over the course of the pandemic).
> If you're walking about in the street, not getting closer than 2m to anyone, and not spending much time in close proximity to anyone, the mask isn't doing much.
This is a general-purpose argument which explains away the existence of community spread, which we know was happening (33m US cases later...). Especially given what we now know about air vs surface transmission, people were clearly spreading it to each other last spring in ways that masks would have mitigated. Knowing what we now know about the difficulty of outdoor spread, people by definition were not universally adhering to what you're describing. Leaving aside the non-compliant (some portion of whom would have worn masks despite violating indoor gathering guidelines), many people were unable to avoid this: nursing homes, grocery stores, meatpacking plants, and all manner of essential workers[1] were clearly enough to drive robust spread.
[1] Here's a list of just how expansive the "essential worker" category was in NYS: https://www.lawandtheworkplace.com/2020/03/new-york-state-ma....
(Note that I don't mean that as a criticism, just a note that your postulated world of 100% of people never coming within 2m of anyone, including outside, is not reflective of reality)
But that wasn't people waking past each other in the street, that was people working with each other in poorly ventilated spaces.
Public health officials during the early stages fully expected all the other recommendations they were making to be taken up: proper lockdowns, vigorous test and trace with good quality supported isolation.
If you're looking at "late lockdown with poor test and trace" then yes, you're right, not pushing masks doesn't make much sense. But it's odd to focus on the mask advice and not the late lockdowns.
Yes, this is my point. There were tons of people (most people?) who didn't/couldn't live their lives without coming into contact with other people's spread, and these people were not recommended to wear masks either.
This was particularly true in the beginning of the pandemic, when the non-scientifically-literate and non-digital-natives had yet to adapt to which behaviors were safe[1]. Masks were a simple, common-sense, zero-cost recommendation which predictably ended up being sound.
> Public health officials during the early stages fully expected all the other recommendations they were making to be taken up: proper lockdowns, vigorous test and trace with good quality supported isolation.
If you don't see this as gross incompetence, I don't know what to tell you. Assuming perfect compliance with specific measures and throwing defense in depth out of the window is shockingly stupid from multiple perspectives: scientifically, epistemically,
> it's odd to focus on the mask advice and not the late lockdowns.
I don't know anyone who defends locking down late. I know plenty of people who defend the severe and constant failures of our public health authorities. It's a much more interesting topic with much more profound implications. What's particularly fascinating about it is the _manner_ in which people defend these failures: Talk to a dozen people, and you'll get 13 highly-confident, mutually-contradictory and individually weak excuses. It strongly suggests to me that there's some weird psychological underpinning to this behavior, and that the expressed excuses are just window dressing.
(To be clear, I don't intend this as a jab against you, but as a phenomenon that's interesting in the aggregate. Your comments in particular are more thoughtful than most I come across on this topic)
[1] In the very early, high-uncertainty days of the pandemic, I had a (highly-educated and successful) uncle in his late 70s tell me not to get takeout and to wipe it down thoroughly if I did, right before saying that he only ever left the house to go to the _grocery store_. I tried telling him he had it precisely backwards (yes, this was clear from the evidence even that early), but his model stuck in his mind like a superstition and fear is a strong deterrent to changing one's mind.
My guess is it was some combination of uncertainty about effectiveness in the general public and wanting masks to be available for healthcare workers, so they ran with the messaging they did. IMO if they didn't want to make a statement that could lead to hoarding in the early days they should have just said nothing about masks until production was ramped up. Masks are such a minimally invasive preventative measure that given uncertainty about their effectiveness you would normally err on the side of encouraging.
Besides, you could make the same argument for something like wearing a helmet while bike riding. I'm sure there are situations where false peace of mind is a problem, but I don't see why we should assume mask wearing would be one of them.
At the time they were obviously operating with limited information, but it's crazy to me that people continue to defend the early pandemic mask messaging. They screwed up, it happens, but it should be acknowledged and there should be a post mortem.
How many people have you seen wearing clear plastic face shields or bandannas tied around their face like Ol' West banditos, with the bottom open? How about with the mask pulled down below their nose? (Disclaimer: I did that the other day; I was at the optometrist and my breath was fogging up the lens thingy.)
The early pandemic mask messaging was wrong. A postmortem might very well find that they made the best recommendations they could based on what they knew.[1] Unless you've already decided that they screwed up because they're lying idiots.
[1] See https://news.ycombinator.com/item?id=26138301: "(I note that there was a meeting of epidemiologists in March, 2020, where famously, no one wore masks. How far are you willing to to go to lie?)"
If I recall, the CDC was recommending treatment that worked against past similar viruses. This one turned out to be spread in a completely different way than typical.