Epidemic analysis of COVID-19 in China by dynamical modeling

Liangrong Peng; Wuyue Yang; Dongyan Zhang; Changjing Zhuge; Liu Hong

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.02. 16.20023465 doi: medRxiv preprint of COVID-19 since its onset in Mainland * , Hubei * , and Wuhan (Beijing and Shanghai are not considered due to their too small numbers of infected cases on Jan. 20th). With respect to the parameters and initial conditions listed in Table 1 , we make an astonishing finding that, for all three cases, the outbreaks of COVID-19 all point to 20-25 days before Jan. 20th (the starting date for public data and our modeling). It means the epidemic of COVID-19 in these regions is no later than Jan. 1st (see Fig. 5d ), in agreement with reports by Li et al. 5, 33, 34 . And in this stage (from Jan. 1st to Jan. 20th), the number of total infected cases follows a nice exponential curve with the doubling time around 2 days. This in some way explains why statistics studies with either exponential functions or logistic models could work very well on early limited data points. Furthermore, we notice the number of infected cases based on inverse inference is much larger than the reported confirmed cases in Wuhan city before Jan. 20th.