It's not enough for vaccines to exist. People have get vaccinated. That has not happened (enough).
How do you know the curve wasn't flattened? I don't know whether it was or not. It seems the only way to find out for sure is to compare the curve to what it would have been in an alternate timeline.
How do you know the curve wasn't flattened? I don't know whether it was or not. It seems the only way to find out for sure is to compare the curve to what it would have been in an alternate timeline.