Epidemic analysis of COVID-19 in China after Wuhan was restricted

Background In 2019, Coronavirus Disease caused Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection appeared in Wuhan, Hubei Province, China. The disease is highly infectious. Wuhan, Hubei Province decided restrict personnel movement on January 23.We analyze relevant data to show the situation of the COVID-19 epidemic in China. Methods The data was classified according to Hubei group, non-Hubei group, Hong Kong, Macao and Taiwan group, and Chinese Mainland group, and analyze the current situation and trend of the epidemic. Results There was an explosive growth in the early stage of the epidemic. The epidemic situation began to improve in about two weeks after Wuhan was restricted,and the situation in non-Hubei was significantly better than that in Hubei.


Introduction
In December 2019, Wuhan, Hubei Province, China, had some pneumonia of unknown causes, all of which were related to the local South China seafood market [1] . According to the investigation of Chinese Center for Disease Control and Prevention(CCDC), the pathogen of pneumonia is a new type of coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).
The virus is highly infectious, forming a clustering outbreak in Wuhan in a short time. Since January is around the Chinese Lunar New Year, there are a large number of people returning to their hometown.
In order to avoid the further spread of the virus, Wuhan, Hubei Province decided on January 23 to restrict the movement of people in Wuhan,close all foreign transportation hubs in Wuhan. So far, it has been 23 days since Wuhan was closed. We have collected all the information about the COVID-19 epidemic caused by SARS-CoV-2, and made a summary analysis report on the information.

Methods
Through the collection of COVID-19 epidemic information from January 10 to January 14 by the National Health Committee of the People's Republic of China and the Health Committees of all provinces and cities in China.The epidemic information was classified and analyzed according to Hubei group, non-Hubei group, Hong Kong, Macao and Taiwan group, and Chinese Mainland group, and analyze the current situation and trend of the epidemic, and compare the differences in severe rate, cure rate and mortality between Hubei and non-Hubei regions.

Statistical analysis
All the data were expressed as mean ± standard deviation,and all the statistical analyses were done using the Graphpad Prism 8.0 software. The independent Student's t-test was used to compare the data between two groups. In both cases, differences with P < 0.05 were considered statistically significant.

Results
Since the outbreak of the disease was found in Chinese Mainland until February 4, the number of new patients per day continues to rise. After February 4, there was a downward trend, that is, 13 days after restricting the movement of people in Wuhan, the national epidemic began to improve. In order to help Hubei Province control the epidemic more quickly, so that suspected patients can be treated more quickly, A novel coronavirus pneumonia diagnosis and treatment plan(trial version fifth) was launched in the National Health Committee of the People's Republic of China in February 12th [3] .
"Clinical diagnosis" has been added to the classification of diagnosis in Hubei Province, that is,suspected cases with imaging characteristics of pneumonia, but there is no evidence of etiology. As a result, there was an explosive increase in the number of newly diagnosed cases on February 12, and then they recovered to their previous levels and showed a downward trend. In Chinese Mainland, the severe rate of patients with COVID-19 is relatively stable at 19.03% ± 3.48%. The cure rate was on the rise in the first few days when the outbreak did not occur.From January 16 to January 27, the cure rate of patients continued to decline after the outbreak. With the control of epidemic situation and the standardization of diagnosis and treatment, the cure rate has gradually increased to more than 12%. It can be predicted that the cure rate will gradually increase. Although there is no completely effective treatment plan for COVID-19 at present, due to the progress of medical intensive care technology, the mortality rate of patients with COVID-19 in Chinese Mainland is basically stable at 2.48% ± 0.64%. Before the specific treatment plan comes out, the mortality rate will not change much (Fig. 1).
Hubei is the main gathering place of the epidemic,80% of the patients with COVID-19 in China are concentrated in Hubei Province at present. Therefore, the epidemic situation in Hubei is similar to that in Chinese Mainland. The change of the epidemic situation in Hubei will affect the overall development of Chinese Mainland (Fig. 2).
The epidemic situation in non-Hubei area is much lighter, Since February 3, the number of new patients per day has continued to decline significantly, that is to say, 12 days after the restriction of Wuhan City, there has been a significant improvement. It can be preliminarily estimated that the number of new diseases will reach a negative growth in the next week. The severe rate of patients with COVID-19 in non-Hubei area has been declining slowly since the beginning of the epidemic. At present, the critical rate is only 7.45%. It is believed that it will continue to decline in the future. The cure rate in non-Hubei areas has been on the rise, and now it has reached 27.80%. In non-Hubei area, patients with COVID-19 have mild illness and low mortality rate. At present, the mortality rate is only 0.69% (Fig. 3).
Due to the great difference between Hubei and non-Hubei areas, the severe rate, cure rate and mortality of Hubei and non-Hubei areas were compared. It can be found that the severe rate and mortality of non-Hubei areas are significantly lower than those of Hubei (Table).
Due to the special geographical location of Hong Kong, Macao and Taiwan and the prevailing policy with the Chinese Mainland, the overall epidemic situation in Hong Kong, Macao and Taiwan is relatively slow to rise, but there is no obvious downward trend at present, and the current new cases are mainly concentrated in Hong Kong.Macao and Taiwan have not seen new patients for about one week in a row (Fig. 4).

Discussion
The pathogen of COVID-19 is a new type of coronavirus belonging to the Beta Coronavirus genus.