Epidemiological Model for COVID-19 in China

Background. The epidemic of coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 first broke out in Wuhan, Hubei Province in China, and then spread quickly worldwide. Objective. This study aimed to dissect the spread and end of the epidemic in China with a precise mathematical model. Methods. Various data were obtained from the official websites of the Chinese National Health from January 20 to July 8, 2020. The Chinese study participants were divided into three groups, namely, Hubei (including Wuhan), nationwide without Hubei, and Henan. The basic reproduction number (R0), effective reproduction number (Rt), and gender and age ratio of COVID-19 were calculated, and the epidemic’s predicted curves or fitting curves with peak time and end time were plotted with SIR model. These predicted curves were compared with actual scatter plots. Results. The fitting curve of the Hubei group showed a parabola with a peak on February 18, 2020, with 51,673 cases and the gradual decrease of infected patients, which culminates with a downhill after May 2020. During early outbreak, the highest recorded R0 was 6.13, which declined gradually forming a S-type curve, and it approached zero in early May. Similar to Hubei group, the fitting curve of the nationwide without Hubei group also showed a parabola, recording a peak of 9145 cases on February 10, 2020. At first, its R0 was as high as 2.35 but declined to zero in early April. The epidemic in the Henan group also reached its peak on February 10, 2020, and ended in early April as well. Conclusion. The epidemic development of COVID-19 in China followed the shape of parabolic curves. This model provides insights into how to strategize for epidemic control.