Wednesday, April 29, 2020

Whats The date of China's First Corona Virus case?

According to the Johns Hopkins University data base the earliest available data for China is 548 cases on January 22nd 2020. According to the Oxford University COVID data base, the earliest available data for China is 27 cases on January 1, 2020. So the first case would most likely have occured in December 2019 as many scholars have speculated.
I fit a logistics curve [ F(t) =A/(1+exp(-b(t-to))] to the Oxford data to derive an estimate of the first case.  The best fit to the China data is given by the following parameters: A= 85,000, b=0.18, to =72 (t is number of days from first case), with an Rsquare of 0.996. The results are shown in the following Graph. Using this ccurve we determine that the first case in China, likely occurred around 1st Decemeber 2019:

  This is much earlier than all other estimates, though there have been speculative reports that a Wuhan doctor identified the case of a new type of Flu in the Animal Market in Wuhan as early as November, but there is little evidence to back this claim.

No comments: