The claim here is that 1) CDC knew masks were effective but 2) decided to ignore that to preserve stocks. For you to support claim 1 all you need to do is post

The claim here is that 1) CDC knew masks were effective but 2) decided to ignore that to preserve stocks. For you to support claim 1 all you need to do is post links to the meta-analyses or randomised control trials that show the effectiveness of masks to prevent the spread of respiratory disease. There are lots of RCTs around mask wearing to prevent the spread of respiratory disease. > And they too admitted to spreading FUD about masks No they didn't. They haven't even changed their advice. Now they say "it may prevent the spread", they definitely don't say "it does prevent the spread", and they're still trying to preserve stocks of medical supplies.