WARNING: If you are not a math whiz, and you don’t understand exponentials very well, the above graph may look deceptively optimistic. Read on to understand why.
The above graph compares how quickly and effectively each country responded to its COVID-19 outbreak, by measuring the outbreak’s growth rate in the 30 days following its start. It shows that USA lags far behind China, South Korea and even Italy, in its efforts to stop the explosive spread.
In this graph, the start of each country’s outbreak is considered to be the day when that country exceeded 100 confirmed COVID-19 cases: day 0. For each day thereafter, the 5-day growth rate is plotted for each country. This allows us to compare the relative effectiveness of each country’s efforts.
The 5-day growth rate is calculated as the percent increase of confirmed cases reported for that day, as compared with the number reported 5 days prior. For example, a growth rate of 100% means that the number of cases doubled in 5 days — a 100% increase from 5 days prior — an explosive growth rate.
As each country responded to its outbreak, the effectiveness of its actions (or inaction) can be seen by observing how quickly and how much it succeeded in reduced the growth rate. For example, South Korea started with an astronomical, off-the-chart growth rate (dotted gray line) in the first 5 days of its outbreak. But by day 13 its aggressive actions to stop the spread had succeeded in lowering the growth rate to about 100%, and by day 20 the growth rate was nearly zero: the outbreak was under control. In contrast, the 5-day growth rate in the USA on day 20 was still 463%. This clearly shows that the USA has been considerably slower and less effective in responding to its outbreak than China, South Korea and even Italy, in spite of the fact that it had weeks of extra lead time to learn from the successes and failures of those countries.
Note this data analysis makes no modeling assumptions or estimates whatsoever. None. Zip. Nada. It uses only officially reported, confirmed COVID-19 case counts.
One tiny glimmer of good news is that the social distancing measures initiated by some state and local governments are starting to help. As of this writing (day 21) the USA’s 5-day growth rate had dropped to just under 300%. UPDATE: As of yesterday (day 27) the USA’s 5-day growth rate had dropped to 146%.
The bad news is that 300% is still an explosively high growth rate. UPDATE: The bad news is that 146% is still an explosively high growth rate. That is more than doubling every 5 days!
This failure by the USA to take rapid effective action to stop the exponential spread of COVID-19 has guaranteed that the USA will now face a national disaster that is much larger than it needed to be.
We need one courageous state governor to step forward and take the lead with other governors, to stop the spread and reduce the magnitude of this disaster. See Stopping COVID-19: Who will fill the leadership void?
3/31/2020: Updated the graph and text with the latest data.
