November 22, 2020

Current Doubling Time for the Number of COVID 19 Deaths in the United States is Decreasing.

The graph below is based on confirmed COVID19 death data reported from the CDC. 

These numbers may lag slightly behind other US reporting sources and will underestimate the actual current death total from COVID19. For that reason, I have calculated and plotted the doubling time in days averaged over a moving seven day period. Doubling time based on the previous seven days average as of 11/16/2020 was 142 days, passing through 246,000 deaths. As of 11/22/2020 this has rapidly dropped to 119 days doubling time passing through 255,000 deaths from COVID10. A graph of the doubling time is shown here. 

November 11, 2020

November 2020: The Rule of 70 and Why Your Hospitals are Feeling the COVID Tsunami Second Wave

Math helps us understand disease spread in populations. A historical view of the rise in cases of COVID19 as the first wave hit in March 2020. The apparent and surprising rise in cases after a long period of just a few cases is typical of the exponential nature of pandemic disease spread in populations. US data seems to have an instant-looking start because there was no significant amount of patient testing, then testing is being increased. Back in March, the actual cases in a population spreading COVID19 were increasing at 12% a day, which the Rule of 70 tells us is a doubling every 6 days. (Graph by KPMitton from CSSEGIS COVID19 data )

1/11/2020 UPDATE: 

This is an update of a posting I wrote back in March 2020 in the first wave of COVID19 just rising mostly in states where COVID19 first arrived. We are in danger again of having local hot spot states now like North Dakota, South Dakota, Texas, where the percent daily increases in cases exceed 5% per day. Early in 2020, we were up to a national average of 12% per day in the first wave. Rates one month ago had dropped well below 1% but now the average US daily increase in cases over last week had risen to 1.5 % per day, but that is the average of all 50 states. In hot states now we are having community locations with over 5% daily increases, and the experience in March will now happen again in November and December 2020. When you have a constant percent daily increase in case number, this percentage factor leads to an acceleration in numbers that can easily and suddenly fill a hospital. Here is the reason, the simple math behind it all. The Rule of 70.