(Combating New Coronary Pneumonia) Zhong Nanshan's team's paper was officially published: only 1.9% of patients have been directly exposed to wild animals

China News Agency, Guangzhou, February 29th (Cai Minjie) Guangzhou Medical University said on the 29th that on February 28th, Zhong Nanshan, a member of the Chinese Academy of Engineering, published a paper online in the New England Journal of Medicine. The paper revealed the research of new crown pneumonia through a large sample study. Clinical characteristics, the study results confirmed that the fatality rate was 1.4%; only 1.9% of patients were found to have a history of direct exposure to wild animals.

As of January 29, 2020, the research team extracted data from 1099 laboratory-confirmed patients with acute respiratory disease (ARD) caused by 2019-nCoV from 552 hospitals in 31 provinces and cities in China.

Guangzhou Medical University said that the study analyzed the distribution characteristics of patients of all ages, the symptoms of infected persons, the way of virus transmission, protection methods, treatment methods, and mortality. The study points out that strict and timely epidemiological measures are essential to curb the rapid spread of the epidemic, and effective treatment methods for the disease still need to be continuously explored.

Only 1.9% of patients have been directly exposed to wildlife

The paper's co-authors Guan Weijie, Liang Wenhua, Professor He Jianxing and corresponding author Professor Zhong Nanshan responded in the public account "NEJM Frontiers of Medicine". The study collected the nationwide new crown patients for the first time. The analysis confirmed the large sample data to determine the Institute's determination. Case fatality rate (1.4%), which is closer to the official data reported by the National Health and Health Commission of China; only 1.9% of patients have a history of direct exposure to wildlife, and 31.3% of residents living outside Wuhan The patient has been to Wuhan in the past 2 weeks, and 72.3% of the patients have been in Wuhan in the past 2 weeks.

The study pointed out that nearly half of the patients with new crown may not have fever at the time of admission, but as the disease progresses, nearly 90% of patients develop fever; clear digestive symptoms are rare, but also point to evidence of new crown virus transmission through the digestive tract (Virus is isolated in the faeces, gastrointestinal tract, damaged mucous membranes, and bleeding), suggesting that all sectors of the community need to pay attention to prevent fecal-oral transmission.

In addition, the study also pointed out that there are indeed new crown patients with positive nucleic acid tests and clinical symptoms but no imaging abnormalities at admission, and the proportion of such patients in non-severe patients is much higher than that in patients with severe new crown infections; it was first clear Patients with severe new crowns are nine times more likely to be admitted to the ICU for invasive mechanical ventilation and death than non-severe patients.

Response latency up to 24 days: median is 4 days

Previously, the study was publicly published on the Medical Preprint (MedRxiV) website, in which the incubation period of up to 24 days caused public concern.

The incubation period is mainly determined by the time when the patient reports the last contact with the source of infection (people in the epidemic area, wildlife) and the time when the first symptoms (including fatigue, cough, fever, etc.) appear. The incubation period of the entire population is different. The researchers used the median and the minimum and maximum values ​​to show the concentrated and scattered distribution of the incubation period.

The study found that the incubation period for each of the patients with a new crown in the severe and non-severe groups was 24 days. However, a careful review of the distribution pattern of the incubation period for the entire population revealed a total of 13 cases (12.7%) with an incubation period greater than 14 days, while only 8 cases (7.3%) had an incubation period greater than 18 days. Estimating the latency of a population based solely on the minimum and maximum values ​​can easily lead to misinterpretation.

In addition, the long-term incubation period for patients who have been living in Wuhan for a long time or in contact with personnel in Wuhan area is mostly 0 days (the contact time is calculated according to the last day); the researchers calculated the unreasonable data and calculated the latest median incubation period. For 4 days. Therefore, in order to better represent the discrete trend of the population, the researchers determined that the interquartile range of the incubation period was 5 days (2 to 7 days).

What are the future research directions?

Regarding future research directions, the research team said that it is urgent to clarify the dynamic characteristics of virus transmission, the transmission pathways, and the virus's addiction to human tissues. Previous studies have been used to predict the changing trend of the new crown epidemic situation in China. However, it has not been properly incorporated into the recent government intervention in various places, the resumption of work across the country, and the closure of cities such as Wuhan and Huanggang on the trend of population epidemics. Therefore, the construction and verification of intelligent predictive models for the spread of viruses in human populations is also the current work focus. (Finish)