April 16 - COVID-19 in Westchester County, NY

Here are the updated charts with data through April 15, 2020. Click on a chart to enlarge it.

We are 30 days into the National 'Slow the Spread' initiative, 37 days since the containment zone in New Rochelle, 44 days (Mar 3) since the first case in New Rochelle (Westchester) was confirmed, and 54 days since that first case had symptoms (Feb 22).  This first case had not traveled abroad recently. He had not caught the virus from a traveler (Patient 0), but from his community. Patient 0, who started the New Rochelle cluster, has not been found. The day after the first case was confirmed, nine of his family and friends tested positive. The virus had probably been circulating in Westchester since early February. At a reproduction rate of 6, there were likely thousands in Westchester infected by the time the containment zone was in place, making it useless. It is time for some reflection.

There is no doubt that the spread has been slowed in Westchester. The exponential explosion of an epidemic has been reduced to a steady stream of about 700 new cases per day with about 70 of those needing hospitalization and 70 persons released. The red line of new cases is flat and the cumulative cases (yellow) can be approximated with a straight line.  About 40 people are dying per day.  All of this has been true for over two weeks.  In engineering we call that 'reaching steady state'.

The case data for NYC and Nassau have this same trend.  There is noise in the data, but the case rate is not showing a decline.  New cases have been between 5 to 10 per 10K for over two weeks. [The decrease in hospitalizations in NYS and NYC contradict this, as do the decreases in deaths in NYC.]

Perhaps we are just on top of a very wide bell curve as seen with Bergamo, Italy below.  Bergamo had about 350 cases per day for almost three weeks before they started dropping.  And then it was another 10 days before they consistently were below 100 cases per day.

Bergamo province has 1MM residents, as does Westchester.  I have assumed the difference in the heights of the curves is due to the excessive amount of testing in Westchester, not any difference in the real infection rate. 2000 people have died in Bergamo compared with 640 so far in Westchester.

Bergamo, who is more than two weeks ahead of Westchester (if you believe my green and orange curves above), has still not reopened its bars, restaurants, and cinemas.