key: cord-0744365-odl1nv4i
authors: Wang, Xiaoqiang; Tian, Weitian; Lv, Xin; Shi, Yumiao; Zhou, Xiaoxin; Yu, Weifeng; Su, Diansan; Tian, Jie
title: Effects of Chinese strategies for controlling the diffusion and deterioration of novel coronavirus-infected pneumonia in China
date: 2020-03-12
journal: nan
DOI: 10.1101/2020.03.10.20032755
sha: 3ac5a0ee56faec83900d1f9da203abb11c7e3110
doc_id: 744365
cord_uid: odl1nv4i

Background: In December 2019, an outbreak of new type of coronavirus named COVID-19 occurred in Wuhan, Hubei Province, China. In a very short time, this virus spread rapidly over China, greatly threatening public health and economic development. The Chinese government acted quickly and implemented a series of strategies to prevent diffusion of this disease. We therefore sought to evaluate the effects of these Chinese strategies for controlling the spread of COVID-19. Methods: From the data of cumulative confirmed cases from provincial Health Commission websites of China, we performed model fitting and calculated the growth speed of cumulative confirmed patients. We further analyzed the time when this growth speed, the rate of the number of new cases, reached its maximum (Speedmax). Comparing different times to Speedmax of different areas in China, we calculated the dates at which the growth speed began to decline in different areas. Also, The number of plateaus were analyzed. Results: The quartic model showed the best fit. For almost all areas in mainland China, the speed of infections reached Speedmax and began to decline within 14 days; exceptions were Hebei, Heilongjiang, Hainan, Guizhou, and Hubei. The number of plateaus was significantly correlated with the emigration index. However, the distance from other areas to Hubei and the number of plateaus had little influence on when a province or area arrived at Speedmax. Once strict intervention strategies were implemented, diffusion and deterioration of COVID-19 were inhibited quickly and effectively over China. Conclusion: Our study suggests that Chinese strategies are highly effective on controlling the diffusion and deterioration of the novel coronavirus-infected pneumonia. These strategies supply experience and guidelines for other countries to control the COVID-19 epidemic.

On December 8, 2019, the first patient with atypical pneumonia of unknown origin was reported by the government of Wuhan, Hubei, China [1] . Since then, the outbreak in Wuhan became an epidemic, rapidly spreading through China and other countries.

On January 1, 2020, a new type of coronavirus was isolated and finally named COVID-19 by the World Health Organization on February 11, 2020 [2, 3] . According to reports [4] , by March 1, 2020, more than 60 countries or areas had reported the confirmed patients with COVID-19, and more than 80,000 patients had been confirmed with COVID-19 worldwide. This has serious implications for both public health and development in China and the world.

To control the diffusion and deterioration of the epidemic of COVID-19 in China, the Chinese government implemented series of strict and unprecedented intervention strategies [5, 6] . For example, on January 21, 2020, COVID-19 was classed as a Class B infectious disease and was controlled as a Class A infectious disease; on January 23, 2020, Wuhan was quarantined to limit the diffusion of patients with COVID-19. All is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . https://doi.org/10.1101/2020.03.10.20032755 doi: medRxiv preprint

For COVID-19 data, we collected the number of cumulative confirmed patients from January 21, 2020 to February 23, 2020 because almost all areas in China began to report confirmed cases from January 21, 2020, and the growth speed reached zero around most areas except Hubei before February 23, 2020. The number of cumulative confirmed patients with COVID-19 in different provinces or areas were acquired from the respective Health Commission websites of China. For COVID-19 data, areas of Hong Kong, Macao, and Taiwan were not analyzed in this study. The emigration index in mainland China was obtained from the Baidu Qianxi website (http://qianxi.baidu.com/).

In this study, we tried multiple curve models to fit known data and times. We used the following models to attempt a good fit of the data: exponential, logarithmic, power function, compound, growth, inverse, logistic, linear, quadratic, cubic, and quartic. Of these, the quartic model showed the best fit, and almost all correlation coefficients reached R 2 > 0.99 for fitted curves in different areas. With time defined as x and January 21, 2020 was recorded as the time "1," the number of cumulative confirmed patients with COVID-19 (y) and time (x) were expressed as the following quartic function:

The growth speed calculation for fitted curves According to fitted curves modeled by known data, we found that almost all fitted = 4 + 3 + 2 + ⅆ + ⅇ . CC-BY-NC-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . https://doi.org/10.1101/2020.03.10.20032755 doi: medRxiv preprint curves showed an "S" form. This suggested that the growth speed of cumulative confirmed cases increased first and gradually decreased after reaching the maximum. Therefore, we analyzed the continuous change of the growth speed and obtained the time when the growth speed reached the maximum (Speedmax) by drawing the derivative function of the fitted curves. When the time was defined as x and January 21, 2020 was recorded as the time "1," the growth speed (y') and time (x) were expressed as the following function:

By drawing the derivative function of the fitted curves, we found that changes of the growth speed (y') were accorded with our hypothesis. The growth speed (y') increases firstly and declines sequentially after reaching the Speedmax.

Before February 23, 2020, the growth speed basically reached zero (new confirmed patients≤1 per day) for most areas except Hubei. If one area reported zero new cases for at least two days, the corresponding number of cumulative confirmed patients with COVID-19 was defined as the plateau number. If an area did not meet the criterion of zero-growth speed for two days, then the number of cumulative confirmed patients on February 23, 2020 was recorded as the plateau number.

In this study, is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . https://doi.org/10.1101/2020.03.10.20032755 doi: medRxiv preprint zuotu.91maths.com/, and the point of Speedmax was calculated by this website as well.

The heat map of China was generated by the drawing instrument from http://www.dituhui.com/.

First, we performed model fitting of different areas in mainland China except for Xizang and Qinghai because the confirmed number of cases were too few in these areas to model. The fitted curves were good, and all correlation coefficients R 2 > 0.99 except for those in Jilin (R 2 = 0.989) and Hubei (R 2 = 0.988). Areas were divided into three parts: areas adjoined to Hubei (Figure 1 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. .

areas. This suggested that the spread of COVID-19 was controlled more quickly and effectively in Zhejiang. More detail about the number of plateaus is shown in Supplementary Table 1 .

COVID-19, a new and severe epidemic, has threatened public health and economic development in China [7] . As of March 6, 2020, the number of cumulative confirmed cases of COVID-19 has reached 100,000 worldwide, and some countries such as Korea, Japan, Italy, and Iran are also suffering from the rapid spread of COVID-19 [4, 7, 8] . The need for greater attention and intervention strategies to curb the spread of COVID-19 around the world is of paramount importance.

To inhibit the spread of COVID-19 as quickly as possible, the Chinese government took actions rapidly and implemented a series of strategies [5, 6, 9] is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. According to our study, we found that these Chinese strategies for controlling the diffusion of COVID-19 are significantly effective and powerful. By implementing multiple Chinese strategies, the growth speed of confirmed patients reached Speedmax and began to decline within 14 days in almost all areas of mainland China. Yang et al. [9] also reported that a five-day delay in the implementation of the Chinese strategies is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. .

The present study has certain limitations. In this study, we simplified the model analysis and performed model fitting with known data. Although the classical susceptible-infectious-removed (SIR) and susceptible-exposed-infectious-removed (SEIR) models were not adopted, the quartic model showed a good fit to known data. This helps us to learn the trends of cumulative confirmed cases quickly and easily.

However, our fitted models were all based on known data as it was more appropriate than forecasting future data trends. In addition, the changes in trends of basic reproduction number (R0) are not discussed in our study. The effects of Chinese strategies will be better understood if the time to Speedmax and changes in R0 are discussed together. Third, more data of different infectious diseases and studies are needed to verify the effectiveness and value of the index Speedmax.

In conclusion, by analyzing the time to Speedmax, our study suggests that Chinese strategies are highly effective on controlling the diffusion and deterioration of the Novel Coronavirus-Infected Pneumonia. These strategies therefore provide experience and effective guidelines for other countries to control the diffusion of COVID-19. Table 1 Conflicts of Interest: The authors declare no conflicts of interest is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . https://doi.org/10.1101/2020.03.10.20032755 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 12, 2020. . https://doi.org/10.1101/2020.03.10.20032755 doi: medRxiv preprint

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Funding: None