The title map is from the official website of the New England Journal of Medicine, and this article is from WeChat public number: Zhongxin Jingwei (ID: jwview ) , author: Gao Ying
On March 1, a reporter from Sino-Singapore Jingwei learned from Guangzhou Medical University that in the early morning of the 28th, U.S.A., the academician Zhong Nanshan’s team dissertation “Clinical Features of Coronavirus Disease in China 2019” (Clinical Characteristics of Coronavirus Disease 2019 in China) (NEJM) Published online, the first authors are Guan Weijie, Liang Wenhua, Professor He Jianxing, and corresponding author Professor Zhong Nanshan.
Research shows that as of January 29, 2020, the research team extracted 1,099 laboratory-confirmed new crown virus infections caused by SARS-CoV-2 from 552 hospitals in 31 provinces, autonomous regions, and municipalities. Disease (Covid-19) patient data. This study analyzed the distribution characteristics of patients at different age groups, symptoms of infected persons, contact history, imaging performance, treatment methods, and clinical outcomes. (including mortality) < / span> etc. 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.
Below, Sino-Singapore Jingwei will take you through the seven questions that this research focuses on.
The mortality rate (1.4%) is lower than recently reported figures
It is written that, although the total number of deaths associated with COVID-19 is high, the mortality rate appears to be lower than SARS and the Middle East Respiratory Syndrome.
“The fatality rate we have determined (1.4%) is lower than the recently reported fatality rate, most likely due to differences in sample size and case inclusion criteria. Our findings are more similar to official Chinese statistics, the latter It shows that as of February 16, 2020, the mortality rate of 51,857 COVID-19 patients was 3.2%. Since mild patients and patients without medical treatment were not included in this study, the real-world mortality rate may be lower. “
Over 50% of patients have no fever at the beginning of admission
The study found that the most common symptoms of COVID-19 patients were fever and cough, but only 43.8% of patients had fever symptoms at admission. As the course of the disease progressed, 88.7% of patients developed fever during their hospital stay. Nausea or vomiting and diarrhea are less common, with only 5% and 3.8% of patients experiencing these symptoms, respectively.
▲ Research on clinical characteristics of patients Source: New England Medical Journal official website
The study emphasizes that although it is clear that digestive symptoms are rare, it also points out thatEvidence (virus isolated from feces, gastrointestinal tract damage mucous membranes, bleeding sites) , suggesting that all sectors of society need to pay attention to prevent fecal-oral transmission.
Only 1.9% of patients have a history of wildlife exposure
Of the patients included in this study, 3.5% were medical staff; 1.9% had a history of wildlife exposure; 483 patients (43.9%) Residents of Wuhan. Of the patients living outside Wuhan, 72.3% had a history of contact with Wuhan residents, of which 31.3% had been to Wuhan; 25.9% of non-Wuhan residents had neither been to Wuhan nor had a history of contact with Wuhan residents.
The incubation period is up to 24 days
This study found that in the severe and non-severe group, one patient each had a latency of 24 days and a total of 13 patients with an incubation period greater than 14 days. (12.7% ) , and only 8 cases (7.3%) . Estimating the latency of a population based solely on the minimum and maximum values can easily lead to misinterpretation.
In addition, patients who have been living in Wuhan for a long time or have contact with personnel in Wuhan area have an incubation period of mostly 0 days. (contact time is calculated on the last day) . After excluding these unreasonable data, the researchers recalculated and obtained the latest median incubation period of 4 days. Therefore, in order to better represent the discrete trend of the population, the researchers determined that the interquartile range of the latency period is 5 days. (2 days-7 days) .
The research team said that the incubation period is mainly based on the time when the patient reports the last contact with the source of infection (infected area personnel, wildlife) and the first symptoms (including fatigue, cough, fever, etc.) . 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.
No imaging abnormalities at the time of consultation
The study 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 these patients in non-severe patients is much higher than that in patients with severe new crown infections.
Of the 975 CT scans performed at admission, 86.2% had abnormal results. The most common manifestations of chest CT are ground glass shadows (56.4%) and bilateral lung patchy shadows (51.8%) . And 157 (17.9%) among 877 non-severe patients and 5 (2.9%) of 173 severe patients had no imaging or CT abnormality. At admission, 83.2% of patients had lymphopenia.
Severe patients have a much higher risk of compound endpoint events than non-severe patients
The primary composite endpoint was admission to the intensive care unit (ICU), mechanical ventilation, or death. Primary composite endpoint events occurred in 67 patients (6.1%), including 5.0% admitted to the ICU, 2.3% receiving invasive mechanical ventilation, and 1.4% of deaths.
Forty-three of the 173 critically ill patients (24.9%) had a primary composite endpoint event. In all patients, the cumulative risk of the composite endpoint was 3.6%; in critically ill patients, the cumulative risk was 20.6%.
How to distinguish between new coronary pneumonia and influenza?
The research team also found that some clinical features of Covid-19 are similar to SARS-CoV. Fever and cough are the main symptoms, and gastrointestinal symptoms are uncommon. These characteristics suggest that SARS-CoV-2 has a different host compared to SARS-CoV, MERS-CoV and seasonal influenza.Subjectivity (tropism) .
The proportion of Covid-19 patients who did not have fever at the time of admission was higher than SARS-CoV (1%) and MERS-CoV (2%) infected patients, so if the definition of surveillance case focuses on detecting fever, patients who do not have fever may be missed. Lymphopenia is common and severe reductions have been achieved in some cases, which is consistent with the results of two recent reports.
The research team said that although SARS-CoV-2 and SARS-CoV have higher species similarity, some clinical characteristics can distinguish Covid-19 from SARS-CoV, MERS-CoV and seasonal influenza. . For example, seasonal flu is more common in respiratory clinics and wards.
For future research directions, the research team said that it is urgent to clarify the dynamic characteristics of virus transmission, the route of transmission, and the addiction of the virus to human tissues. Previous studies have been used to predict the changing trend of the new crown pneumonia epidemic in China, but it has not been properly incorporated into the recent strong government intervention measures in various places, the national resumption of work, 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.
This article comes from WeChat public account: Zhongxin Jingwei (ID: jwview) , author: Gao Ying