IIRC, they advised against masks because (1) they didn’t know it was airborne and (2) there was a huge PPE shortage and discouraging a run on PPE would allow more to go to healthcare professionals. In the beginning there was a ton of investigation on how big of droplets the virus could subsist in (we were all wiping down packages) and it wasn’t clear how the virus was transmitted. As they got more actionable information, they revised their guidance. Not saying they were perfect but there was some fog of war during the spring of 2020 that can’t be dismissed.

The coventional wisdom in epidemiology that diseases can be separated into those spread by aerosols and those spread by droplets. This turns out to be complete nonsense based on a single flawed decades old study claiming particles larger than 5 microns can't stay in the air for an extended period of time, when the actual limit is orders of magnitudes higher. The failure of the public health establishment to realize this reflects long-standing issues the field has with appreciating research done by experts in other fields. Aerosol scientists knew all this, and tried to tell them.

Luckily the CDC has admitted it's mistake, though they haven't properly updated guidance accordingly.

https://www.wired.com/story/the-teeny-tiny-scientific-screwu...

> A) all these experts somehow conspired in record time to broadcast very similar lies to a global audience.

If many people have similar incentives they can act similarly without explicit coordination.

> B) that all hospitals, doctors, nursing homes across the world ALL failed to stock vital supplies.

Not all, but many. This was obvious to anyone watching at the time. Remember the doctors wearing trash bags in the USA? Remember the patients in parking lots?

> The "more actionable information" you speak of, is btw, shoddy beyond belief. There are three major pieces to this:

I have no clue where you got this idea this is the evidence. The evidence for masks is physics: We know COVID is spread by aerosols, and we know masks filter aerosols. That's all you need.

Completely genuine question here. Have masks actually been shown to help or not help? We must have learned something about it during all this.

There is just no chance that an n95 being worn even somewhat properly wouldn't significantly reduce your chance of catching COVID or any airborne, respiratory virus.

My anecdotal experience, and I think it matches with lots of other people, is that I never caught covid for most of the pandemic while wearing an n95 and even travelled and was out in public quite a bit. It wasn't until after I and most other people stopped wearing a mask in public that I caught it. It could have been due to virus mutation or whatever, but I had quite a few close calls where I was around infected people but wearing a mask and did not catch it. I also have a large extended family, so lots of people caught it and there was always a homegrown investigation on where they got it. Every single time, there was always some maskless gathering a week or two before where multiple people became infected or a family member that brought it home.

This study from the CDC website indicates masks have benefits, with increased benefits from certain types of masks - N95 masks seem to be the most effective. https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm

Yes, I know, the irony!

You can discard data on this point from the USA because our mask mandates were weak — N95 not required even in medical offices — and compliance was always poor at best.