In early 2020, the CDC/NIH establishment decided - without any scientific basis - to claim COVID would be transmitted like influenza. That is, by small droplets of bodily fluids. That, of course, was perfectly wrong.
In short order, it was widely known that COVID was airborne. But that same establishment then doubled down on masks and social distancing, even though they knew they wouldn't work against an airborne virus, for reasons which have become obvious.