I have seen articles that suggest over 1/2 of children in NYC were infected with this in Jan-Mar time frame. They would likely have been thought to have a cold, sniffles, or simple flu. Only antibody testing of a broad swath of that population will let us have any idea of the real numbers. (Of fatality divided by infections).
I hope it’s true, I just wish the studies showing it to be true were not so riddled with errors.