COVID-19 March 27, 2020

The trends for today are interesting and complicated.  Yesterday, I noted that the short-term trend had flattened a bit and that the 100,000 case mark would be pushed off by a day.  For almost two weeks, the exponential model predicted 100,000 by the end of the day on March 26.  That changed a few days ago, and I suggested that was due to a decrease in new cases in New York, which accounted for nearly half the total cases.  New infections in New York have flattened out a bit.  They are still growing, but not at the same rate as before.  Besides the flatter short-term best-fit line (first figure below), the influence of New York is most obvious in the daily rate of change (second figure).   Note that last three days in the daily rate of change curve clearly fall below the long-term trend. 

I also noted yesterday that other states were exploding, and that they could cause a secondary increase in infections.  This appears to be happening.  New Jersey, which I thought had also stabilized based on data from prior days went from 727 cases to 2,474.  This almost certainly has to be testing issues, but it may also indicate continued uncontrolled growth.  Perhaps more concerning is the rapid increase in mostly southern states where the first line of defense appears to be prayer rather than science.  AL went from 68 to 197.  MS went from 57 to 108.  MO went from 101 to 146.  And so on.

In the daily rate of change graph, the rate of change is once again on a fairly steep upward climb.  There was an offset three days prior, which brought a temporary one day reprieve.  States outside of NY are now undergoing explosive growth.

Unfortunately, the total number of dead is now large enough to begin tracking.  Today, I introduce the total death charge and the daily death rate.  Unlike infections which have testing issues, the dead are always counted.  We can't be entirely sure that we still aren't missing some deaths that were not properly associated with COVID-19, but the data should be overall more reliable. 

The downside of tracking deaths is that it is a lagging indicator.  People that die from COVID-19 were infected a week or more ago.  The average incubation period prior to symptom onset is about 5 days.  Then it takes three or five (or more) days until the victim succumbs to the disease.  So, the death numbers on a given day are a measure of reality something like 10 days ago.  The total deaths as of yesterday, March 26, was 1147.  That's more representative of the population that was infected on March 16 and that began to show symptoms around March 21.   If we go back to March 16, we find there were only 4,672 total cases.  On March 21 there were 23,710. We are now at 100,000 total cases.  The reality of today's situation will not be reflected in the deaths for many days to come. I'll also note that the 10-day exponential fit for total deaths is exceeding the long-term fit.