April 18 - COVID-19 in Westchester County, NY

The normal charts are below.  They are followed by more news on antibody testing.

Westchester County continues to have a steady flow of New Cases, as does NYC and the surrounding metro areas.

The Percent Testing Positive is slowly coming down, but is slightly correlated with testing volume (the more tests the lower the percent testing positive). Westchester was consistly over 40% in early April and has been below 40% for the last three days.

Deaths in Westchester dropped below 30 for the first time in 10 days (Orange Line).

The epidemic curve for Westchester is getting wider and wider! Compare it to the curve from 18 days ago, April 1!  Nobody has proved that 'Slowing the Spread' is really reducing total infections or deaths....It is probably just delaying them.

Gaussian Fit of New Case Data in Westchester from April 1

Antibody Testing and the True Spread of Infection

Knowing how many people have been infected has a profound impact on the calculated risk of this virus.  If many people are asymptomatic, the mortality rate of the virus is smaller than thought.  If hard-hit populations, like Westchester, are really 50% immune vs. the confirmed cases of 2%, then the risks of relaxing personal contacts are less.

The length of time it has taken to do a random antibody study in New York is a bit frustrating.  Westchester is the ideal location for such a study. The spread is wide (over 2% confirmed infected), very deep viral testing (amost 6% of the population has been tested), and Westchester is well past its 8th week of high-infection-rate when the antibody production should be maxed. 

Mount Sinai (NYC) has an FDA approved test to measure the level of antibodies.  They have not done a large random study yet, but their work shows that patients had antibodies 14 days after infection with yet higher levels of antibodies at 21 days when the viral load was 'pretty much gone.' 

A study in Santa Clara County suggests that about 50 times more people were probably infected in the county than shown by the confirmed cases.

A similar study in Gangelt, Germany found a 15% infection rate vs. less than 1% confirmed cases.

    

All passengers on the Diamond Princess were tested for the virus (not antibodies). 634 of 3711 (17%) tested positive, many of whom had no symptions.  Who knows how many had the antibodies? 

San Miguel, Colorado offered the antibody test to its 8000 residents to help United Biomedical evaluate its test. Less than 1% had antibodies and another 2% were "borderline."  At the time there were no known cases in San Miguel. One month later there are only 13 confirmed cases in San Miguel.  Why didn't they test it in Westchester where the results would have been more interesting?  Maybe they were really looking for a 'clean' population so they could confirm false positives, which appears to be a real problem with these tests.

Do a majority of people in the NYC metro area now have the antibodies?  Let's find out now!