Estimating doubling time of US COVID-19 pandemic in Canada, Germany and the US

In this post I estimate the doubling time of the COVID-19 pandemic in the US, Canada and Germany using daily death count data.  At the current rate, COVID-19 deaths will exceed 2009 H1N1 deaths by early April in the US, and deaths due to COVID-19 are accelerating faster in the US than the rate of coronavirus deaths in Italy at the beginning of the pandemic there.  Germany and Canada show lower rates of spread than the US, but do not yet show evidence of “flattening of the curve”. The WorldOMeter website has been keeping track of confirmed COVID-19 daily case and death counts by country: https://www.worldometers.info/coronavirus/country/us/ The time trends in the number of deaths is likely much more reliable to track the spread of COVID-19 compared to trends in the number of case counts, because case counts are heavily affected by changes in test availability.

United States

The cumulative number of COVID-19 deaths in America at the time I first began this post (March 21st) looks like this: Screen Shot 2020-03-21 at 3.12.37 PM I downloaded the current data (I regularly update this post), and fit an exponential to the number of new deaths per day to estimate the pandemic doubling time:   Screen Shot 2020-04-01 at 10.15.44 AM During the 2009 H1N1 pandemic, there were 12,469 deaths in the US. On March 20th, when I originally wrote this post, my model estimate was April 7th when the number of COVID-19 deaths would exceed the 2009 flu deaths.  Sadly, that estimate has turned out to be exact.  The COVID-19 pandemic is now worse than that of 2009, and will unfortunately become much worse than it already is.

The doubling rate of deaths in the US is accelerating faster than the doubling rate of deaths in Italy near the beginning of the pandemic there.  Here is a plot of the number of deaths per day after the day at which each country achieved at least 10 deaths.  You can see the US trend line is diverging from the Italian trend line: Screen Shot 2020-04-01 at 10.19.29 AM

Canada

Fitting an exponential to the daily number of deaths in Canada yields: Screen Shot 2020-04-01 at 10.21.45 AM The pandemic appears to be spreading slower in Canada than in the US. There were 740 deaths in Canada due to pandemic influenza during 2009.  At the current doubling time, deaths due to COVID-19 will exceed the deaths due to 2009 pandemic influenza by April 21st. Canada’s rate of rise in deaths is currently significantly less than that of Italy at the same point in their pandemic: Screen Shot 2020-04-01 at 10.25.10 AM

Germany

Fitting an exponential to the daily number of deaths in Germany yields: Screen Shot 2020-04-01 at 10.26.41 AM The rate of rise in deaths in Germany is currently less than the rate of Italy at the same point in their pandemic: Screen Shot 2020-04-01 at 10.40.10 AM

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