What do you mean, there is zero data supporting "this"? "This" meaning COVID might have been around before we really knew about it?
The antibody testing can give you this data.
This meaning there's no proof that having an antibody to a virus makes one immune?
If that is the case why is anyone bothering with treatment with convalescent plasma?
I'm not sure I'm getting your point.
“This” is the idea that “most people don’t know they have it” and “lots of people have herd immunity”. PROPER antibody testing “can” give you data...but just suppose that, once the data comes in that there IS currently no “herd immunity”, and no, there IS no large population that has had the virus without symptoms.
And I would want to know a LOT more about the false negative rate of the test.
I’m just sick and tired of rampant speculation over and over and over and over.