Covid-19 Doubling Time

(addendum: When this page was written the use new cases rise was no longer exponential. However as of July 13, 2020 new cases growth in my own Tri-Cities Tennessee region is exponential and the doubling time is, unfortunately, significant again.

This project is to visualize data from the Johns Hopkins collection of Covid-19 data.  Originally, the goal was to calculate and display the doubling time for the total cases and the R value, a crude estimate of how many new cases each case causes.

The usual graphs of total cases in linear and logarithmic scales are well known from the worldometer website.  In March one could see an upturning curve in the normal linear scale and a straight line in the logarithmic scale, which indicates exponential growth of the epidemic.  But the rate of exponential growth was harder to quantify, so I calculated the doubling time and displayed it in a separate graph.

In March the total was doubling about every three days and reproduction rate R was about three new cases generated by every case until March 16, when the President asked us to avoid groups of more than 10 and to avoid discretionary travel and states began closing schools and businesses.  Within a week the logarithmic graph was no longer straight but curving downward and the regular scale graph was less upward curving and had begun a straight slope, indicating an end to exponential growth and beginning of linear growth. 

On May 19, as this is written, even the linear growth is slowing, the R value is hovering around 1 and the doubling time is rising and no longer a useful measure of exponential growth.  Now the more important graph is that of new deaths reported, because the graph of new cases is more likely to be affected by the changing availability of diagnostic tests than the graph of deaths. 

Finally, I aggregated the data from the 17 Virginia and Tennessee counties that Ballad Health serves to get a sum of cases and deaths in our region.  Thes are Virginia: Lee, Wise, Scott, Dickenson, Buchanan, Russell, Washington, Tazewell, Smyth, and Tennessee: Johnson, Sullivan, Carter, Hawkins, Washington, Unicoi, Greene, and Hancock.

You can also view countries in the world, some subdivided in regions, and counties within the U.S.  You can also click the Download button to download the latest data from Johns Hopkins each day. 
Please notify of any errors or suggestions to covid19@eastridges.com.  Thanks. 
(Download the program below.)