There were not only the asymptomatic cases — there were people who had symptoms but never visited the doctor, thinking it was just another flu bug, or not wanting to get quarantined. It doesn’t take a rocket scientist to figure that out.
There are tons of people being told to just stay home if you think you have mild symptoms. Don’t go to an emergency room, don’t waste your doctor’s time. In fact they are are not hospitalizing unless you can’t breathe anymore.
These are the people who haven’t been counted as infected.
So NIH and CDC didn’t goof up. The mitigation itself necessitated rules that kept people with mild symptoms from being counted. We won’t know their numbers until tests are widely available for all, both pathological and antibody. In NYC we just have 30,000 tests coming available tomorrow, aside from those for people who had serious symptoms.
In short, the original estimates were off because of that conflict, between mitigation needs and the need for counting asymptomatics.
It was also interesting what she said about herd immunity. Everyone’s casting that term about but it is only properly used in the context of vaccination.