Robert Prost emails:
I wanted to share with you, my take on the corona virus situation in the United States.
But first, a brief introduction. I am professor emeritus at the Medical College of Wisconsin in Milwaukee.
I have a PhD in Biophysics and spent my career in MRI-based research, mostly on brain tumors.
I check the Johns Hopkins’ website every day for the progress of the epidemic and I had a feeling about the numbers I’ve been seeing.
The website: https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 is very good.
The daily case number totals can be extracted by mousing over each plotted point in the graph in the lower right hand corner of the screen.
The curve at first looks daunting, it seems to be shooting straight up. But being at least in part a mathematician, I wondered about the velocity of this upward move in cases.
If the velocity was going up, the epidemic would be accelerating, the epidemic would be worsening. If going down, it would be getting better (slowing).
So I plotted the data and took the first derivative with respect to time. What it shows is that the velocity of the epidemic in the US is definitely slowing, and quickly.
While the number of confirmed cases continues to rise, it is rising more slowly. If there were a confounding effect from increased surveillance (more testing revealing yet more cases), the apparent velocity should be going up.
Instead, it is going down. So I believe the effect to be real, and thus I believe we are witnessing the beginning of the end of the epidemic. While this data says nothing about the potential for re-emergence in the fall or following spring, it does suggest that we have in fact, flattened the curve.
UPDATE: A follow-up email from Robert is posted here.