April 22 - COVID-19 in Westchester County, NY

We are 36 days into the National 'Slow the Spread' initiative, 43 days since the containment zone in New Rochelle, 50 days (Mar 3) since the first case in New Rochelle (Westchester) was confirmed, and 60 days since that first case had symptoms (Feb 22). It is time again to step back for some perspective.

In those 36 days, the virus erupted in New York City and then spread out from there.  There could have been other 'Patient 0s' who started clusters in Queens, Nassau, or Rockland, but it is very possible that all of this started with one person in New Rochelle or Manhattan.

Since then, 800 people have died in Westchester County (about 0.1% of the population) and they are still dying at about 30 per day. The total confirmed cases in Westchester are about 2.5% of the population.  Westchester is quite large -- 30 miles from its border with the Bronx to its northern villages where people like the Clintons, Martha Stewart, and Ralph Lauren live.  The infection is concentrated in areas with denser populations and more Hispanic and African American residents.

Map of Westchester County showing Total Cases by municipality.  Data is about 10 days old.

Although Westchester does not release data by zipcode or percapita (as other entities have been doing), these dense areas appear to have an incidence of disease of well over 3%.  For reference, in Rockland County (across the Hudson River) there are several zipcodes where the incidence is over 3%.  See the red areas below.  These areas in Rockland have a high Hasidic Jewish population. The density of households is one aspect they share with the hardest-hit areas in Westchester.

Rockland County Total Cases.
  Hudson River is shown in blue on the right.  Westchester is to the right of the River.

The good news is that Westchester has had no problem handling the patients needing hospitalization. That is surprizing considering the extent of the infection.  The explanation appears to be in the large number of beds per 10K residents in Westchester compared to the rest of the state. Westchester has 30 hospital beds per 10K compared with 7 per 10K for the rest of NYS. Hospitalizations in Westchester peaked at about 1000, far short of the 3000 beds available.  The $15MM overflow hospital built by the Army Corp of Engineers was not needed.

Of the County's 25,000 cases, over 15,000 are already resolved.

New Cases in Westchester dropped to the lowest number since March 22, almost exactly 4 weeks ago. If the last three weeks is a predictor of the future, Westchester may still be on the plateau.

The gaussian fit suggests that New Cases will not fall below 60 (~2% of total cases) until May1 at the earliest.  The IMHE model was updated and released yesterday for the entire state of New York. It predicts that by May 8, deaths will fall below 60 per day (~2% of total deaths).  Of course, IMHE has almost always been wrong (explain to me how they become more certain the farther they predict into the future? I guess they can be certain that the deaths will not fall below 0, duh.  The 95% certainty range for May 8 is 7 to 175 deaths. We can come back later and check on that.  By the way, on April 1, their model had 95% confidence that the death rate would be 0-50 on May 1!)

Westchester deaths are definitely still on a plateau of about 30 per day (orange line).  The number hospitalized is falling, but is still close to the peak of around 1000.

The NYC metro area does appear to be trending lower in New Cases.