Forecasting and Analysis of Time Variation of Parameters of COVID-19 Infection in China Using An Improved SEIR Model

Abstract

Abstract Background: Due to the emergency pandemic threat, the COVID-19 has attracted widespread attention around the world. Common symptoms of infection were fever, cough, and myalgia fatigue. On January 31, 2020, the World Health Organization (WHO) declares this outbreak a Public Health Emergency of International Concern (PHEIC).Methods: In order to study the spread of the novel coronavirus pneumonia, this paper proposed an improved SEIR model to simulate the spread of the virus, which includes the effect factor of government intervention. The model parameters are determined based on the daily reported statistical data (up to February 8) of confirmed, suspected, cured, and death. According to utilize the spread rate, the probability of infection of the suspected, the probability of the suspected becoming a confirmed one, the cure rate, the mortality rate, and the quarantine ratio, we performed simulations and parameter calibrations at three region levels, i.e., China, Hubei and non-Hubei respectively. In addition, considering that the government initiated effective prevention and control measures after the outbreak, this paper dynamically estimates all the parameters of the proposed model.Results: The simulation reveals that the parameters of non-Hubei region are not significantly different from Hubei’s. Hubei Province has a high transmission rate, low cure rate, high probability of infection, low effective quarantine rate. since January 31, with the continuous strengthening of epidemic prevention and control measures, all parameters of the model have changed significantly. The parameters of Hubei and non-Hubei regions have the same trend. The trend of all parameters is now moving in a direction that is conducive to reducing the number of confirmed, suspected and fatal cases.Conclusions: The number of infections of the virus initially showed a rapid increase in the trend, and the number of infectious case showed a clear downward shape. With the government to take a variety of prevention and control measures and the efforts of the general medical staff, the number of infection curve on February 22 appeared in the top of the arc pattern, indicating that the inflection point began to appear, but the decline in the number of infections slowly.