The results of case study indicate that the epidemic spread from Hubei Province in December 2019. As of February 11, 1386 counties and districts in 31 provinces were affected. The epidemic curve showed that it reached the peak from January 23 to 26, and the trend of the incidence was observed to decline. A total of 1716 medical workers were infected, 5 of them died, and the crude mortality rate was 0.3%.
It is mentioned in the paper that in late December 2019, a group of pneumonia cases with unknown causes occurred in Wuhan, China, which attracted the attention of health authorities. On December 31, 2019, China CDC sent a rapid response team to Wuhan. One by one, the possible causes were excluded, including influenza, avian influenza, adenovirus, severe acute respiratory syndrome coronavirus (SARS CoV) and Middle East respiratory syndrome coronavirus (mers COV).
The epidemiological investigation indicates that the case infection may be related to the South China seafood market in Wuhan. On January 1, the local government closed the South China seafood market, disinfected the market, and required active case search and emergency monitoring. On January 3, the Chinese government informed the World Health Organization (who) of the outbreak.
Early cases suggest that the new coronavirus may not be as severe as SARS CoV and mers cov. However, the rapid increase in the number of cases and increasing evidence of human to human transmission suggest that the virus is more infectious than SARS CoV and mers cov.
In the discussion of the paper, the research team pointed out that the early stage of the outbreak was associated with SARS and mers, and found a pathogen closely related to coronavirus, which had never been described before, indicating potential hospital transmission and so-called super disseminator event, that is, one sexual exposure caused more than 10 consecutive cases. Unfortunately, the novel coronavirus did spread the infection through the hospital. Novel coronavirus pneumonia has yet to be demonstrated in any of the medical institutions that provide services for patients with new coronavirus pneumonia.
But up to now, the specific causes of infection and failure of protection of medical staff still need to be further investigated.
At the same time, some important scientific questions remain to be answered, including the identification of animal hosts, the determination of infection period, the identification of transmission routes, the development of effective treatment and prevention methods (including the development of simple detection reagents, the development of drugs and vaccines).
The key results are as follows:
A total of 72314 cases were reported, including 44672 confirmed cases (61.8%), 16186 suspected cases (22.4%), 10567 clinically diagnosed cases (14.6%) and 889 asymptomatic infections (1.2%). Among the basic characteristics of the confirmed cases, most of them are between 30-69 years old (77.8%), 51.4% are male, 22.0% are farmers or workers, 74.7% are Hubei Province, 80.9% are mild / moderate.
The paper points out that the cases are classified as suspected cases, confirmed cases, clinically diagnosed cases (only limited to Hubei Province), asymptomatic infections. Suspected cases are novel coronavirus based on symptoms and exposure history. Clinical diagnosis is for suspected cases with pneumonia imaging characteristics (only for Hubei province). Confirmed cases are suspected cases with positive viral nucleic acid test results. Asymptomatic infection is a new coronavirus pathogen positive for respiratory tract specimens.
The date of onset of asymptomatic infection was replaced by the date of positive laboratory test. The onset date of other cases is defined as the date when the case self reports the onset of fever or cough in the epidemiological investigation.
Second, the number of deaths, crude mortality and mortality density
Among the 44672 confirmed cases, there were 1023 deaths, with a crude mortality rate of 2.3% and a mortality density of 0.015/10 person days. That is to say, the average mortality risk of each patient observed for 10 days was 0.015. The highest crude mortality was 14.8% in the age group u2265 80 years old. The crude mortality rate of male was 2.8%, which was 60% higher than that of female and 1.7% for female.
By occupation, the highest crude mortality rate of retirees was 5.1%. The crude mortality rate of Hubei Province (2.9%) was 7.3 times higher than that of other provinces (0.4%).
The crude case fatality rate of unreported patients with comorbidity was about 0.9%, while the case fatality rate of patients with comorbidity was much higher. Cardiovascular disease was 10.5%, diabetes was 7.3%, chronic respiratory disease was 6.3%, hypertension was 6.0%, and cancer was 5.6%.
Among them, the crude case fatality rate is expressed as a percentage by dividing the number of confirmed cases by the total number of confirmed cases (denominator).
Third, age distribution and sex ratio
The age group accounted for 89.8% of the total confirmed cases in Wuhan City, 88.6% in Hubei Province (including Wuhan) and 86.6% in China (including Hubei). The proportion of cases in the elderly group over 60 years old is 44.1% in Wuhan, 35.1% in Hubei (including Wuhan) and 31.2% in China (including Hubei).
The ratio of male to female was 0.99:1 in Wuhan, 1.04:1 in Hubei and 1.06:1 in China.
Fourth, spatial and temporal distribution
Novel coronavirus infection was first confirmed in Guangdong in January 19th. This is the first novel coronavirus pneumonia reported in Hubei province outside China.
Novel coronavirus pneumonia novel coronavirus pneumonia novel coronavirus pneumonia was reported in 83 counties in 23 provinces as of January 22nd. In January 30th, Tibet reported the first confirmed case of new crown pneumonia imported from Hubei in January 30th. Up to now, 30 new provinces in the 30 provinces have been reported to have reported a new crown pneumonia outbreak.
The team analyzed the novel coronavirus pneumonia cases in 5 different periods by retrospective analysis of the date of onset of the reported cases.
As of February 11, a total of 44672 confirmed cases (74.7% in Hubei) have been reported in 1386 counties and districts of 31 provinces in China, of which 0.2% are in Hubei before December 31, 2019; 1.7% are in 113 counties and districts in 20 provinces before January 10, of which 88.5% are in Hubei; 13.8% are before January 20 Among the 627 counties in 30 provinces, Hubei accounted for 77.6%; 73.1% of the cases occurred before January 31, and distributed in 1310 counties in 31 provinces, of which Hubei accounted for 74.7%.
As of February 11, 2020, novel coronavirus pneumonia confirmed case report date and incidence date curve.
The epidemic curve of all patients was drawn according to the time of onset. January 24-28 was the first epidemic peak, and on February 1, the abnormal high value of the single day onset appeared, and then gradually decreased.
The epidemic curve of confirmed cases was drawn according to the date of onset and the date of report. The number of patients increased rapidly at the beginning of January, reached the first epidemic peak from January 24 to 28, and then decreased slowly. However, on February 1, there was an abnormal high value of one-day incidence, and then decreased gradually.
The epidemic curve on the reporting day showed that the number of reported cases increased rapidly after January 10, reached the epidemic peak on February 5, and then decreased slowly.
The peak of medical staff cases may occur on January 28. Novel coronavirus pneumonia (1716 novel coronavirus) cases were found among 3019 medical staff in 422 medical institutions providing new treatment for the patients with acute pneumonia. 5 of them died. There may be infection due to non occupational exposure.
Novel coronavirus pneumonia confirmed cases, severe cases and death cases reported by medical staff from December 8, 2019 to February 11th in Hubei, Wuhan
According to the analysis of 1688 confirmed cases with severity, there are 1080 cases in Wuhan, accounting for 64.0% of the total number of medical staff in the country, 394 cases (23.3%) in other areas except Wuhan in Hubei, and 214 cases (12.7%) in 30 provinces (districts / cities) except Hubei. The proportion of severe cases was 17.7% in Wuhan, 10.4% in Hubei and 7.0% in China except Hubei. According to different periods of time, the proportion of severe cases in Wuhan Medical Staff decreased gradually from 38.9% at the highest to 12.7% in the first ten days of February.
Attachment: list of new coronavirus pneumonia emergency response Epidemiology Group of China Center for Disease Control and Prevention
Feng Zijian, Li Qun, Zhang Yanping, Wu Zunyou, Dong Xiaoping, Ma Huilai, Yin Dapeng, Lu Ke, Wang Dayan, Zhou Lei, Xiang nijuan, Ren Ruiqi, Li Chao, Wang Yali, Li Dan, Zhao Jing, Li Bing, Wang Rui, Niu Yan, Wang Xiaoye, Zhang Lijie, sun JinFang, Liu Boxi, Deng Zhiqiang, Ma Zhitao, Yang, Liu Hui, Shaoge, Li Huan, Liu Yuan, Zhang Hangjie, Qu Shuquan, Luo Wei , Dan duo, Hu Yaohua, Hou Lei, Zhao Zhenping, Liu Jiangmei, Wang Hongyuan, Pang Yuanjie, Han Yuting, Ma Qiuyue, Ma Yujia, CHEN Si, Zhang Xueying, Li Wei, Yang ruotong, Li Zewu, Guo Yingnan, Liu Xinran, bahabaike, Yin Zhaoxue, Xu Juan, Wang Shuo, Xiao Lin, Xu Tao, Wang Limin, Qi Xiao, Shi Guoqing, Tu Wenxiao, Shi Xiaoming, Su Xuemei, Li Zhongjie, Luo Huiming Ma Jiaqi