Of course the “masks don’t work” was pure, transparent, bullshit from the very beginning. It didn’t even pass the smell test. Now if the argument was “please save masks for healthcare workers first, they’re higher risk” that would be fine. But “they don’t work”? Fuck off.

Edit: I’m referring to the CDC here, not you personally, dear HN commenter.

At least by telling people masks don't work... peer pressure would keep them from buying them?

Here he claims masks (general) do not protect you. But they do protect healthcare workers. It amazes me that he was willing to put two such contradictory claims in the same tweet. It was just such a transparent lie. Given the context and implication, I think it is referring to "medical" grade masks including N95, surgical masks, etc.

Another part of the confusion is that early on (six weeks ago) the assumption was that the virus spread like the flu, i.e. via droplets from coughing and sneezing. Masks alone (without face shields) are of little benefit for droplet-spread disease because they don't protect your eyes. Now we know the virus spreads via aerosols which are generated by talking or even breathing. Cloth masks do indeed help for aerosols by trapping virus particles electrostatically and by increasing humidity, both of which keep the virus out of your respiratory tract. Or so the latest thinking goes.

Hanlon's Razor applies, but this virus is also an insidious bastard that behaves very differently from what public health experts had expected.

First of all, there are very different rationales for healthcare workers and the general public to wear masks. Healthcare workers know they will be exposed, so the protocols must be damn near perfect. The general population does not know if they’ll be exposed, they’re trying to work in aggregate to put a drag on the viruses’ spread; even partially effective mask wearing slows that down. The general population can also practice social distancing, while healthcare workers must spend hours in close personal contact with positive patients by the nature of their jobs, vastly increasing their risk.

Second, this ignores the fact that mass mask usage prevents you from getting someone else sick. This is in fact exactly why surgeons wear surgical masks. Since we’ve known for months that this disease has asymptomatic transmission, the public health rationale for even cloth mask usage was obvious from the very beginning.

Without the rest of the kit, and without careful adherence to correct donning and doffing, there are at best marginal benefits to mask wearing.

There's some concern that those marginal benefits are eliminated if people wearing masks go on to engage in risky behaviours. These behaviours include increased touching of their face (often without immediate handwashing afterwards), reductions in distance between people, increase in frequency of leaving the home, etc etc.

PPE is designed to mitigate a completely different level and type of risk. PPE is designed for medical professionals who by the very nature of their job must spend hours in physical contact with known sick patients. The protocols must be strict because failure means guaranteed infection.

I on the other hand have no obligation to physically touch random strangers, thank god, and don’t have to go interact with known sick people. Instead I’m trying to provide some protection for myself, and trying to work in aggregate to reduce the risk that asymptomatic carriers spread the disease while doing essential activities. “Marginal benefits” in this context is also known as “reducing R0”, which is absolutely a public health goal.

Now all of that is a good argument for saving N95 masks for medical workers and relying on surgical or cloth masks for the general public, especially in the light of PPE shortages. But that is an entirely different argument from “masks don’t work”.

What's the point of wearing the mask then?

If you're wearing a mask to protect against droplets then maybe you'd get marginal benefits. But if your concern is virus carried in the water vapour that people exhale, then an N95 isn't nearly enough to protect you.

90% what?

It makes no sense to claim "90% effective".

90% reduction in numbers of people infected? Of droplets inhaled? Of droplets exhaled?

"Masks work, don't work" are not cogent arguments.

It's the same with plastic gloves. Their usage in ie. grocery stores etc. may not help as much as incorrect usage may work against the intention. Again the argument is that if you get your hands dirty, you know you need to wash your hands and might think twice before touching face. Even washing hands properly require some training.

We've since learned that less extreme measures may be good enough once you have control, testing and tracking.

A lot of the commentary about the matter is disingenuous. Of course they won't filter out all the infectious agents for all healthcare workers forever. It was a matter of risk mitigation, just as much as shelter-in-place is. Getting infected is a numbers game, as is the live-locking of available hospital capacity.

No, that's not true. Maybe the advice was wrong, but it wasn't "pure, transparent, bullshit." It was always clearly stated that N95s worked if worn properly, but there was a lot of debate if surgical masks would offer much protection or not (they're known to be inadequate for certain viruses). Especially early on, people didn't understand much about this virus, such as the particle sizes involved or if asymptomatic transmission was real or not. There were a lot of factors to weigh in the recommendation in an environment of uncertainty.

> Now if the argument was “please save masks for healthcare workers first, they’re higher risk” that would be fine.

They did make that argument:

https://www.marketwatch.com/story/the-cdc-says-americans-don...

> Most people don’t know how to use face masks correctly, and a rush to buy masks could prevent the people who need them most — health care providers — from getting them, said Dr. Amesh Adalja, a scholar at the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health.

> In fact the U.S. surgeon general recently urged the public to “STOP BUYING MASKS!” “They are NOT effective in preventing general public from catching #Coronavirus, but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!,” wrote Surgeon General Jerome Adams on Twitter US:TWTR

> But “they don’t work”? Fuck off.

It's also pretty clear that they were right that tons of people in the general public don't know how to wear masks correctly. I don't go out much, but when I do there's always a bunch of fools wearing N95s improperly (not using both straps, bunching both straps together behind the head, not shaping the noise area to fit the face). I even see people wearing surgical masks improperly (e.g. not covering the nose, not shaping the nose area, not folding out the material to stretch from the nose to under the chin, etc.).

There's also the issue that the general public is unlikely to follow the kinds of rigorous protocols that make N95s effective in a healthcare setting.

1) Wearing masks is a trainable skill. None of us know how to use condoms initially either, yet literally millions of Americans use them effectively yearly.

2) Masks don’t have to be worn with perfect correctness to produce an effect in aggregate. If mask usage was even 30% effective, this would drop R0 by roughly as much, which is a big freaking deal.

The N95 vs surgical mask is a tricky balance to strike; of course N95 should be saved for those at the highest risk, and if you know your mask will be sprayed with virus droplets, extra precautions must be taken. But that’s much more relevant to medical workers, not those of us who want to reduce risk going to the grocery store.

Not really. Do you have a qualitative fit test handy? Because you need to do a fit test with one to figure out if an N95 you chose actually works properly, even if you're wearing it properly. Healthcare workers are tested, and the kits cost $200 or more.

https://www.medline.com/jump/product/x/Z05-PF07344

https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-...

> [Surgical] Masks don’t have to be worn with perfect correctness to produce an effect in aggregate. If mask usage was even 30% effective, this would drop R0 by roughly as much, which is a big freaking deal.

I think that's why they ended up changing the recommendation.

The problem is that this isn’t the nuance that the Surgeon General or the CDC originally went with. His argument was literally “You can increase your risk of getting it by wearing a mask if you are not a health care provider”, and “STOP BUYING MASKS”, neither of which distinguishes between N95s, surgical masks, and cloth masks.

Most people don't wash their hands properly either, but we tell people to do it because even washing hands poorly is better than not. Even "fools" wearing masks wrong would help more than not having them at all.

The parent is right: was pure, transparent, bullshit. If they were intending to preserve masks for healthcare workers, then just say that. Telling people they don't work was not just stupid, it was dangerous and almost certainly made the situation worse. Don't lie to people about their health.

Stopping other people from catching something you might have is a fantastic reason to ask everyone to wear a mask during a pandemic. It’s actually probably the main reason you’d want to do so, from a public health perspective, because it helps you prevent asymptomatic thread. The idea that the surgeon general would beg everyone to not wear a mask is utter madness.

However I was replying to a comment that was implying surgeons are using them to protect themselves. That is just wrong. There are enough good arguments for masks, one does not need to make incorrect statements.

https://twitter.com/Surgeon_General/status/12337257852839321...

Additionally, the surgeon general has repeated this claim on live television as recently as a week ago. There is no way he's that incompetent.

Of course do not / do protect are simplifications as the effects are not binary. This is needed for communicating with the public, the meaning was "don't help much" vs "make a significant difference".

If the health authorities always used the precise and caveat-ridden language of medical journal papers in order to ensure each sentence is logically correct when interpreted literally, they wouldn't get any messages through.

The guidance about public usage of masks has changed in a lot of countries because the guidance changed from "no evidence that it protects the public from infection enough to make difference in epidemic spread" to "let's take even the small benefit of reducing spray from the potentially infected mask wearers". It's a sensible change when the mask shortages let up.

No need to fan the flames of lightly assuming malice from health authorities, it's a bad time for that.

I agree with you that right now it's absolutely crucial that organizations like the CDC maintain credibility, which is what makes this such a huge problem. Me calling out the lie is not the problem. The lie is the problem.

https://twitter.com/Surgeon_General/status/12337257852839321...

  the masks do protect the healthcare workers

With respect to protection from SARS coronaviruses, wearing just a mask and no eye protection is like a hockey goalie wearing a helmet but no mask.

An apt comparison -- a damage reduction by 66% using only a fabric mask is massively worse than a damage reduction by 95% using proper PPE and procedures. In fact, it leaves you 7 times more likely to get infected (get hurt by a puck). But if anyone tried to sell the NHL-watching public the line that "helmets don't help", they would be rightfully humiliated in public.

When found, copy-cat masks are destroyed at border control, as they also don't provide the benefits to contain contagion.

I had to stop following the WHO and CDC Facebook pages because the value of information they were posting was so poor, I was IMHO better of not having access to it.