Phase- and Epidemic Regions- Adjusted Estimation of the Number of Coronavirus Disease 2019 Cases in China

Abstract

Background: The outbreak of the Coronavirus Disease 2019 (COVID-19) was first reported in Wuhan in December 2019 and gradually spread to other areas in Hubei Province and regions outside Hubei Province in China. After implementation of prevention and control measures in China, the estimation of the epidemic trend is needed so as to predict the possible infection scale and epidemic characteristics of COVID-19, furtherly, to provide potential evaluation criteria for the effectiveness of current prevention and control measures and, to offer theoretical support for current decision-making on infectious disease prevention. Methods: A phase- and region-adjusted SEIR (Susceptible, Exposed, Infectious and Removed) model was applied for modeling and predicting the number of COVID-19 cases in Wuhan, Hubei Province and regions outside Hubei Province in China. Findings: The estimated number of infections would reach the peak in late February 2020 in Wuhan and Hubei Province, which is 55,303–84,520 and 83,944–129,312, respectively. The epidemic peaks in regions outside Hubei Province in China appeared on 13th Feb with the estimated 13,035–19,108 confirmed cases. Wuhan had an infection rate of more than 3,900 per million population as of 18th Feb 2020. In the areas adjacent to Wuhan, the average infection rate was around 550 per million population. In major financial regions (Beijing, Shanghai, and Guangdong) and provinces neighboring Hubei Province, the infection rate was over 10 per million population. Interpretation: It is reasonable to speculate that the outbreak would be braked soon with the very strong prevention measures taken all over China. Current estimation provided evidence for planned work resumption under stringent prevention and control in regions outside Hubei Province in China to further support the fight against the epidemic. Nevertheless, strict prevention and control measures should still be maintained, especially in the regions with high intensity of epidemic such as Hunan, Guangzhou, Zhejiang Province as well as densely-populated cities such as Shanghai and Beijing, considering the possibility of the second outbreak brought by the work resumption and population migration, especially from Hubei Province and high-intensity cities outside Hubei Province. Funding Statement: This work is funded by Medicine and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University (YG2020YQ06), the National Key Research and Development Project (2018YFC1705100, 2018YFC1705103) and the National Natural Science Foundation of China (71673187). Declaration of Interests: All authors declare no competing interests.