How china control corona virus
Materials and Methods
1. Research design:
Describe and analyze the epidemiological characteristics of all COVID-19 cases in Mainland China reported as of February 11, 2020. We used a cross-sectional study design and used the STROBE guide (www.equator-network.org) as a reference, which helps us to conduct in-depth reports on this observational study.
Starting from December 31, 2019, CDCs at all levels across the country have jointly launched a COVID-19 investigation. We extracted all the data from the case report system, and removed the personally identifiable information of all cases during the analysis process to protect personal privacy. This study is a data analysis of information related to the emergency handling of the epidemic, and has been reviewed and approved by the China CDC Ethics Review Committee.
2. Data Sources:
COVID-19 has been classified as a Class B infectious disease. According to legal requirements, all cases should be reported immediately through the infectious disease information system. Information about each case was entered into the system by local hospitals and CDC personnel, who investigated and collected possible exposure information. All case records contain personal ID numbers, so all cases will not be recorded repeatedly in the system. We selected all mainland China COVID-19 cases reported in the infectious disease information system as of February 11, 2020, and after removing all personally identifiable information, we formed a separate data set for analysis. All cases are included in this study, so there is no need to sample a predetermined sample size, and there is no need to consider case inclusion criteria.
3. Variable information:
Collect patient demographic characteristics, diagnosis time, epidemiological investigation time, and report time to the infectious disease information system. If the patient is engaged in any form of work in a medical institution, the occupational variable is classified as medical personnel (that is, this category includes not only doctors and nurses); if the patient has recently lived in Wuhan, traveled, or has been to Wuhan If people have close contact, they are classified as Wuhan-related exposure. The conditional variables of comorbidities are based on the patient's self-reported medical history in the epidemiological investigation, and the medical records of all cases are not used for verification. The severity of symptoms is divided into mild, severe or critical: mild includes non-pneumonia and mild pneumonia; severe symptoms refer to dyspnea, respiratory frequency ≥30/min, blood oxygen saturation ≤93%, PaO2/FiO2 ratio <300, and/or pulmonary infiltration >50% within 24 to 48 hours; critically ill refers to those cases with respiratory failure, septic shock and/or multiple organ dysfunction/failure.
Since variables such as Wuhan-related exposure, comorbidities, and severity of cases are not required when creating records in the infectious disease information system, data on these variables are missing in the information of some cases.
For the epidemiological curve, the date of onset is defined as the date when the case self-reported fever or cough in the epidemiological investigation. Cases are classified into suspected cases, confirmed cases, clinically diagnosed cases (limited to Hubei), and asymptomatic infections. Suspected cases are clinically diagnosed based on symptoms and exposure history; clinically diagnosed cases refer to suspected cases with imaging features of pneumonia (only in Hubei Province); confirmed cases refer to suspected cases with positive viral nucleic acid test results; asymptomatic Infection refers to a positive test for the pathogen of the new coronavirus in specimens such as the respiratory tract. The "onset date" of asymptomatic infection is replaced by the date of positive laboratory test.
4. Statistical analysis:
For confirmed cases, use descriptive statistics of the demographic and clinical characteristics of the case. The crude case fatality rate is the number of confirmed deaths (numerator) divided by the total number of confirmed cases (denominator), expressed as a percentage. At the same time, calculate the number of days of observation for each confirmed case, divide the number of deaths (numerator) of confirmed cases by the number of days of cumulative observation of confirmed cases (denominator) to obtain the case fatality density, expressed as the number of deaths/10 human days.
Using the age at the time of diagnosis of confirmed cases, draw 3 age distribution maps of Wuhan, Hubei (including Wuhan) and China (including Hubei), and calculate the sex ratio between men and women.
For spatio-temporal analysis, the county-level location of each case at the time of diagnosis is used to draw a color map. According to the onset date retrospective of the epidemiological survey after diagnosis, it is divided into December 31, 2019 and January 10, 2020. , 20th, 31st and February 11th five time periods, to report the distribution of the number of cases in the province. The analysis was performed using ArcGIS Desktop software (version 10.6; Redlands, California, USA, Environmental Systems Research Institute).
The epidemic curve is drawn by the number of cases (y axis) and the self-reported date of onset of the earliest clinical symptoms (x axis). The onset dates of confirmed cases and suspected cases are superimposed to show the total number of cases in a period of time. At the same time, the onset date and report date of the confirmed case are made together, which is convenient for comparing the epidemic curve drawn on the onset day and the epidemic curve drawn on the reporting day. The epidemic curves of two subpopulations were analyzed separately: confirmed cases outside Hubei Province (whether there are Wuhan-related exposures) and medical staff cases (confirmed cases and suspected cases).
result
1. Case:
A total of 72 314 cases were reported. Among them, 44 672 confirmed cases (61.8%), 16 186 suspected cases (22.4%), 10 567 clinically diagnosed cases (14.6%), and 889 asymptomatic infections (1.2%) ).
Basic characteristics of confirmed cases (n=44 672). Most are between 30 and 69 years old (77.8%), 51.4% are men, 22.0% are farmers or workers, 74.7% in Hubei Province, and 80.9% are mild/moderate. See Table 1.
Table 1
The number of new coronary pneumonia cases, deaths and case fatality rate nationwide
2. Number of deaths, crude case fatality rate and case fatality rate density:
Among the 44 672 confirmed cases, there were 1 023 deaths, with a crude case fatality rate of 2.3%, and a case fatality rate of 0.015/10 person-days, which means that the average risk of death for each patient observed for 10 days is 0.015. The highest crude case fatality rate in the age group ≥80 years is 14.8%. The crude case fatality rate is 2.8% for men and 1.7% for women. Divided by occupation, the highest crude case fatality rate for retirees is 5.1%. The crude case fatality rate in Hubei Province (2.9%) is 7.3 times higher than that of other provinces (0.4%). The crude case fatality rate for patients with unreported comorbidities is about 0.9%, and the case fatality rate for patients with comorbidities is much higher, 10.5% for cardiovascular disease patients, 7.3% for diabetes, 6.3% for chronic respiratory diseases, and 6.3% for hypertension. 6.0%, cancer is 5.6%. Severe cases accounted for 13.8%, and critical cases accounted for 4.7%. The crude case fatality rate of critical cases is 49%, and the case fatality rate density is 0.325, that is, the average risk of death for each critical case observed for 10 days is 0.325. See Table 1.
3. Age distribution and sex ratio:
Figure 1 shows the age distribution of confirmed cases in Wuhan City, Hubei Province and the whole country. Patients are concentrated in the 30 to 79 years old. This age group accounts for 89.8% of the total number of confirmed cases in Wuhan, 88.6% in Hubei Province (including Wuhan), and 86.6% in the whole country (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 the whole country (including Hubei). The ratio of males to females of confirmed cases is 0.99:1 in Wuhan, 1.04:1 in Hubei, and 1.06:1 in the whole country.
figure 1
As of February 11, 2020, age distribution characteristics of confirmed cases of new coronavirus pneumonia in different regions
4. Time and space distribution:
On January 19, the National Health Commission confirmed the first confirmed case of pneumonia with imported new coronavirus infection in Guangdong Province. This is the first confirmed case of new coronary pneumonia in a province outside Hubei. As of January 22, a total of 301 confirmed cases of new coronary pneumonia have been reported in 83 counties and districts in 23 provinces across the country. Tibet reported the first confirmed case of new coronary pneumonia imported from Hubei on January 30. So far, except for Hubei 30 provinces outside the country have reported the discovery of new coronary pneumonia in two weeks (Figure 2).
figure 2
As of February 11, 2020, confirmed cases of new coronavirus pneumonia have spread from Hubei to the country
Through retrospective analysis of the date of onset of the reported cases, the changes in the geographical distribution of confirmed cases of new coronary pneumonia in the country during five different periods were restored. As of February 11, a total of 44,672 confirmed cases were reported in 1,386 counties and districts in 31 provinces across the country (Hubei accounted for 74.7%, Figure 2E), of which 0.2% of the cases had an onset date of December 31, 2019 Previously, the cases were all in Hubei (Figure 2A); 1.7% of the cases had an onset date before January 10, distributed in 113 counties in 20 provinces, of which Hubei accounted for 88.5% (Figure 2B); there were 13.8 % Of cases had an onset date before January 20 and were distributed in 627 counties in 30 provinces, of which Hubei accounted for 77.6% (Figure 2C); 73.1% of cases had an onset date before January 31, distributed in Of the 1,310 counties in 31 provinces, Hubei accounted for 74.7% (Figure 2D).
The prevalence curve drawn by all patients according to the time of onset (Figure 3A). January 24-28 is the first epidemic peak. The abnormally high value of the single-day onset day appeared on February 1, and then gradually decreased. The epidemic curve of confirmed cases drawn according to the date of onset and the date of report (Figure 3B). The number of cases began to rise rapidly at the beginning of January, reached the first epidemic peak on January 24-28, and then slowly decreased, but on February 1, there was an abnormally high value on the single day of onset, and then gradually decreased. The epidemic curve on the reporting day shows that the number of reported cases rose rapidly after January 10, reached the epidemic peak on February 5, and then slowly declined.
image 3
As of February 11, 2020, the four types of new coronavirus pneumonia cases are based on the onset date curve (A) and the confirmed cases are based on the onset date and report date curve (B)
5. Cases outside Hubei and medical staff cases:
For reported cases outside Hubei Province, the confirmed cases with and without Wuhan exposure history are shown in two colors, and the epidemic curve is drawn according to the date of onset of the patient (Figure 4A). The peak incidence of cases outside Hubei Province is January 24-27. Most cases (68.6%) reported that they had lived in Wuhan or had been to Wuhan within 14 days before the onset of illness, or had close contact with Wuhan patients.
Figure 4
As of February 11, 2020, whether confirmed cases of new coronavirus pneumonia outside Hubei have a history of exposure to Wuhan (A) and all medical staff cases according to the onset date curve (B)
The peak of medical staff cases may occur on January 28 (Figure 4B). Among the 422 medical institutions that provide diagnosis and treatment services for patients with new coronary pneumonia, a total of 3,019 medical staff were infected with the new coronavirus (1,716 confirmed cases), and 5 of them died. There may be infections caused by non-occupational exposure. Analyzing 1688 confirmed cases with severity of illness, Wuhan has 1,080 cases, accounting for 64.0% of the total number of medical staff in the country, 394 cases (23.3%) in other regions of Hubei except Wuhan, and 30 in the country except Hubei. 214 cases (12.7%) in 5 provinces (regions/cities). The proportion of severe cases is 17.7% in Wuhan, 10.4% in Hubei, and 7.0% nationwide excluding Hubei. According to different time periods, the proportion of severe cases among medical staff in Wuhan gradually decreased from 38.9% at the peak to 12.7% in early February (Table 2).
Table 2
From December 8 to February 11, 2019, the country, Hubei, and Wuhan reported confirmed cases, severe cases, and deaths of new coronary pneumonia among medical staff
discuss
The epidemiological characterization and exploratory analysis of 72 314 cases of novel coronavirus pneumonia reported in the mainland of my country were carried out. The main findings include that although the 2019 novel coronavirus is highly contagious, most of the patients have mild symptoms and deaths from gross illness in general The rate is low. Among the deaths, most were patients 60 years of age and older, and had underlying diseases such as hypertension, cardiovascular disease and diabetes.
Another major contribution of this study is the first description of the epidemic curve of 2019 new coronary pneumonia. The overall curve (Figure 3) presents an outbreak pattern. Cases onset in December 2019 may be a small-scale exposure mode; January 2020 may be a spreading mode. The time trend of this outbreak is consistent with the conclusions of previous investigations, that is, there may be wild animal trade in Wuhan Huanan Seafood Market, which makes the new coronavirus from a still unknown wild animal to humans, and then spreads from person to person. [3,8].
The early stage of the outbreak is reminiscent of SARS and MERS, and a pathogen closely related to the coronavirus has been discovered, which has never been described before, heralding potential hospital transmission and the so-called "super spreader" event[8], That is, one-time exposure caused more than 10 consecutive cases. Unfortunately, the new coronavirus did spread through hospitals and infected medical staff. This study described for the first time 1688 confirmed cases by medical staff, most of which were mild patients (85.4%), and the fatality rate was lower than other cases. The main reason is related to age. Medical staff are all working staff, generally under 60 years old, and deaths mainly occur in patients over 60 years old. As of now, there is no evidence that a super-spreader incident has occurred in any medical institution that provides services for patients with novel coronavirus pneumonia.
Through the analysis of the epidemiological characteristics of the new coronary pneumonia that has become a "public health emergency of international concern"[12], it is hoped that the results will be provided to medical staff and health decision makers who are preparing or may be experiencing the new coronary pneumonia epidemic Valuable reference information. The analysis of epidemiological characteristics provides important insights into several key issues in this epidemic and how to design effective control strategies [3]. For example, serious medical staff infections have occurred in some areas of Wuhan and Hubei, but so far, the specific reasons for medical staff infections and protection failures still need to be investigated in depth. In addition, the downward trend of the overall epidemic curve shows that restricting the movement of people, reducing contact, disseminating key prevention information (for example, washing hands, wearing masks, and seeking medical advice) at a high frequency through multiple channels, and mobilizing rapid response from multiple departments help
The country’s timely response to the epidemic has drawn lessons and experiences from the SARS Contain the epidemic.
The country’s timely response to the epidemic has drawn lessons and experiences from the SARS period. It has also been the foundation for China to establish and improve the infectious disease surveillance system and public health infrastructure over the past ten years to detect the epidemic early and respond quickly. We must remain vigilant and adjust and improve prevention and control strategies and measures based on the ever-growing new understanding of new coronary pneumonia. At the same time, emergency preparations are made for a more serious epidemic that may occur.
A major advantage of this study is the large number of reported cases. The study also has several limitations. First of all, a considerable proportion of cases in the analyzed data have not been confirmed by nucleic acid testing, because nucleic acid testing is time-consuming, labor-intensive, and requires professional equipment and technical personnel. However, all cases have been clinically diagnosed, and a high proportion of cases have been investigated by professional epidemiologists. Secondly, some cases in the study lack some limitations
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