> Look it's always been known since the very early days of Wuhan crisis that masks will significantly reduce spread and risk (from past smaller pandemics & the nature of transmission of this virus)
We have a lot of research into mask use, both to protect the wearer and to protect people around the wearer.
Can you point to any that you think CDC should have been using to support mask wearing in the general public?
You can argue about the level of evidence required (organisations like CDC strongly prefer well run meta analyses or a bunch of RCTs), but to say "it's always been known" simply isn't true.
I'd argue it has always been known that masks would protect both patients and wearers even from first principles and also how past pandemics with a less infectious virus were handled in Asia and from how common cold and flu dropped as a side effect.
The virus spreads via droplets exhaled or emitted from nose and mouth. What happens when something obstructs that flow - the % of droplets going in & out & velocity decreases and likelihood of transmission reduces. Why do you think surgeons wear masks - it's both to protect the patient and the surgeon from droplet borne infections.
What was unknown was whether it was economical to wear masks widely and whether there were supplies, not that it would work.
We have a lot of research into mask use, both to protect the wearer and to protect people around the wearer.
Can you point to any that you think CDC should have been using to support mask wearing in the general public?
You can argue about the level of evidence required (organisations like CDC strongly prefer well run meta analyses or a bunch of RCTs), but to say "it's always been known" simply isn't true.