key: cord-0811498-yw7psy0a
authors: Mi, Yan-ni; Huang, Ting-ting; Zhang, Jun-xia; Qin, Qi; Gong, Ya-xin; Liu, Si-yu; Xue, Hui-min; Ning, Chang-hua; Cao, Lei; Cao, Yong-xiao
title: Estimating instant case fatality rate of COVID-19 in China
date: 2020-04-24
journal: International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases
DOI: 10.1016/j.ijid.2020.04.055
sha: 5c3d2689ee96236e928b88b62778411fa39f2bbb
doc_id: 811498
cord_uid: yw7psy0a

Abstract Objective The outbreak of coronavirus disease 2019 (COVID-19) in China has been basically controlled. However, the global epidemic of COVID-19 is worsening. We established a method to estimate instant case fatality rate and cure rate of COVID-19 in China. Methods We collected 82735 confirmed cases released officially by Chinese authorities from Dec 8, 2019 to April 18, 2020. The estimated diagnosis dates of deaths and cured cases were calculated based on median cure time or median death time of individual cases. Afterward, instant fatality rate was calculated according to the number of deaths and cured cases on the same estimated diagnosis date. Results In China, the instant case fatality rate of COVID-19 was 3.8-14.6% from Jan 1 to Jan 17, and then gradually declined and stabilized at 5.7% in April. The average case fatality rate in China was 6.1%±2.9%. While, the case fatality rate was 1.0±0.4% in China except Hubei. The cure rates of COVID-19 were 93.9%±2.9% in China, and stabilized at 94.3%, while it was 99.0%±0.4% in China except Hubei. Conclusion The instant case fatality rate of COVID-19 in China was much higher than that in China except Hubei. The case fatality rate of COVID-19 in China was underestimated.

COVID-19 cases has passed 2,160,000 worldwide (Organization, 2020a) . More than 74 82,000 cases were confirmed and more than 4,600 cases have died in China. At present, 75 the outbreak in China has been essentially controlled. More than 100 countries are now 76 facing and dealing with COVID-19 epidemic around the world such as America, Spain, 77 Italy, Germany Iran, France, the United Kingdom and South Korea，etc. 78 For an unprecedented epidemic such as COVID-19, it is important to assess its (Zhang, 2020) . However, 96 there were still 38909 hospitalized cases among 44672 confirmed cases. There is a large 97 deviation in the COVID-19 case fatality rates from the current literature and official 98 announcements (Battegay et al., 2020) . Therefore, it is unreasonable to integrate all 99 hospitalized patients into the denominator to calculate the case fatality. Another reason 100 is that the death dates are later than the diagnosis dates during the period of the outbreak, 101 which could increase the error of the estimation of case fatality rate. These two reasons 102 will lead to underestimate the case fatality rates of COVID-19 when the epidemic is 103 still ongoing. China is the first affected and the first recovery country in the outbreak.

The unsuccessful estimation of the case fatality rate of COVID-19 may have a 105 considerable impact on global epidemic prevention, and make the global pandemic 106 worse.

The WHO is calling on every country to act with speed, scale and clear-minded In the present study, we established a method to estimate the instant case fatality The case fatality rate is defined as the percentage of deaths in the total number of 135 confirmed cases of COVID-19. After treatment, the confirmed patients had two 136 endpoints: either cure or death, which would occur on dates later than their confirmed 137 cure time and death time. In order to estimate the case fatality rate, firstly the cure time, 138 and death time, then confirmed dates of cured cases and deaths should be calculated. fatality rate of COVID-19 was ranged from 3.8% to 14.6%. The case fatality rate was 255 less than 10% (3.8-9.1%) from Jan 1 to Jan 13, 2020, continuously increased to 14.6% 256 on Jan 17, and then gradually declined and stabilized at 4.2% on April 7, which is an 257 estimated diagnosis date. However, depending on the corrected data reported by the 258 government taskforce of Wuhan at April 17, the case fatality rate was increased to 5.7% 259 from previously estimated 4.2%. The average case fatality rate in China was 6.1±2.9%.

The case fatality rate of COVID-19 in China except Hubei was 0.5% to 3.4% in the 261 early stage from Feb 15 to Mar 25. Thereafter, the case fatality rate tended to be stable 262 and less than 1%. The average case fatality rate in China except Hubei was 1.0±0.4%.

The case fatality rate of COVID-19 in China except Hubei was obviously lower than 264 that of China. The instant cure rate of COVID-19 in China was high at 95% in early January, 269 gradually declined to 85.5% in the middle of January, and then slowly increased and 270 stabilized at nearly 95.9% on April 7, which is an estimated diagnosis date( Figure 5A ). In brief, on February 17, WHO's director general said that patients with COVID-306 19 have a "mild disease and will recover" and that it is fatal in 2% of reported cases. 

In this study, we assumed that the cured patients or the dead patients experienced in mid-Jan, 2020. Since then, the treatment concept and methods have been, the 320 treatment level has improved, and the treatment procedure has become increasingly e 321 standardized. The case fatality rate gradually declined and stabilized at 4.2%. However, April 17, the case fatality rate was increased to 5.7% from previously estimated 4.2%.

The average case fatality rate in China was 6.1 %. The case fatality rate of COVID-19 325 in China except Hubei was 1%, which is lower than that in the country. We assumed that the dead patients experienced a course of MD after diagnosis.

The estimated diagnosis date (DeD) of death should be the date on MTD before the The instant cure rate of COVID-19 in China was high at 95% in early January, 276 gradually declined to 85.5% in the middle of January, and then slowly increased and 277 stabilized at nearly 95.9% on April 7Mar 25, which is an estimated diagnosis 278 date( Figure 5A) 

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