Gao Fu also said that retrospective investigation is one of the responsibilities of CDC, to find the culprit, conduct retrospective investigation and guide future prevention and control. Our prevention and control has not stopped, and we havent slept for a month.
This is a retrospective analysis
The paper, which was published on January 29, us time, was led by China CDC, and was jointly completed by professionals from Hubei CDC and Hong Kong University. The studys co authors included Feng Zijian, deputy director of the China CDC, and Yang Bo, director of the Hubei CDC. Co authors also include Gao Fu.
In this paper, the team analyzed 425 laboratory confirmed cases reported as of January 22, 2020. The analysis shows that the median age of the first 425 patients is 59 years old, and the male is 56%. By January 1, 2020, the majority of cases (55%) were related to the wholesale market of South China Sea products, while the subsequent cases were 8.6%. The mean incubation period was 5.2 days, and the 95th percentile was 12.5 days. In the early stage, the size of the epidemic cases doubles every 7.4 days, the average continuous interval of infection is 7.5 days, and the basic infection number (R0) is estimated to be 2.2.
Based on this information, the paper claims that there is evidence that there has been interpersonal communication between close contacts since mid December 2019.
Novel coronavirus pneumonia is widely questioned because of its more information about the outbreak of the new crown pneumonia.
On January 31, China CDC published an article entitled explanation of China CDC on publishing articles in New England Medical Journal, which said that the paper was based on the retrospective analysis of 425 confirmed cases (including 15 medical staff) reported as of January 23, 2020, and all cases had been released to the society before the writing of the paper. The 15 cases mentioned in the paper were announced to the public by academician Zhong Nanshan, head of the high level expert group of the national health and Health Commission, on the evening of January 20 and the early morning of January 21, respectively.
The viewpoint of interpersonal communication in close contacts in December 2019 proposed in this paper is a retrospective inference based on the epidemiological investigation data of 425 cases.
The paper also said that timely publication of the survey results in academic journals would help professionals at home and abroad to timely understand the characteristics of the disease, jointly evaluate and study the epidemic situation, and improve prevention and control strategies.
However, this article did not respond to when the CDC came to the conclusion that interpersonal communication occurred among close contacts in December 2019.
In terms of infectious epidemiology, retrospective research is really very important. Without retrospective research, we can not understand the incidence of infectious diseases more clearly, and then formulate the prevention and control strategies of infectious diseases. Therefore, after the outbreak of an infectious disease and case diagnosis, the first thing that will appear is the epidemiological investigators.
An epidemiologist also told reporters that retrospective research is the basic work of infectious diseases, which must be carried out according to the existing cases. In the absence of cases, no one can observe the development path of the virus.
In fact, the data of 425 cases is not enough to show the characteristics of the new virus. It can only show the situation in the past and (425 cases) at that time and how it will develop in the future. We need to continue to observe. Said the epidemiologist.
How to launch retrospective analysis
The novel coronavirus pneumonia is determined by the unknown etiology pneumonia monitoring mechanism.
In order to identify pneumonia cases and improve the sensitivity of early detection, the research team developed a customized monitoring program to identify potential cases on January 3, 2020.
For novel coronavirus pneumonia, the initial work case definition is based on SARS and Middle East respiratory syndrome (MERS). After obtaining new information on confirmed cases, the epidemiological criteria defining suspicious cases were updated on January 18, 2020.
Once suspicious cases are found, a joint team composed of China CDC, provincial, local and municipal CDC and county CDC will be notified to carry out detailed field investigation and collect respiratory tract samples, which will be intensively tested in the Institute of viral disease prevention and control of China CDC.
A joint team of CDC and local CDC staff also conducted detailed field surveys of all suspected and confirmed cases. Through interviews with infected persons, relatives, close contacts and medical staff, they collected epidemiological data to determine the contact history of patients two weeks before the onset of the disease, including the date, number, frequency and method of contact with wild animals, especially the wild animals available in the South China seafood market in Wuhan. In addition, the researchers collected information about exposure to any relevant environment, as well as contact with other people with similar symptoms.
All epidemiological information collected in the survey, including contact history, schedule and identity of close contacts, was cross checked.
After this route, the team obtained epidemiological information of 425 cases.
The basic number of infections is about 2.2
The reason why retrospective analysis of infectious diseases is important is to see clearly the laws of infectious diseases. Only when we see clearly the enemy can we make better prevention and control.
In addition to the above questioned content, what other information does this paper reveal that deserves attention?
In this paper, the researchers estimate the growth rate of the epidemic by analyzing the data of cases between December 10, 2019 and January 4, 2020.
Novel coronavirus pneumonia is estimated to be about 2.2 of the basic infection rate in the data before January 4th, which means that infection is transmitted to 2.2 other people on average. In terms of novel coronavirus pneumonia, the paper says that the challenges of control include the obvious presence of many mild infections, and the limited resources of isolated cases and the isolation of their intimate contacts.
However, increased awareness of the outbreak and increased availability and utilization of tests in recent weeks will increase the proportion of infections identified.
A chart used in this article shows a decline in the number of cases after January 11. However, the paper also claims that it is probably due to uncertainty in recent cases and delays in identification and reporting, rather than the real inflection point of incidence rate.
Considering that the availability and use of test kits will increase over time, the paper said that great care should be taken in explaining the rate of case growth in January. In summary, the results also show that in the early stage, the size of cases doubles every 7.4 days. The average continuous interval was 7.5 days. The paper also reminds that the urgent next steps include determining the most effective control measures to reduce communication within the community. With more understanding of the epidemiological characteristics and the dynamic mechanism of the case onset, the definition of the work case also needs to be improved. At the same time, cases need to continue to be monitored to detect any changes in epidemiology, for example, infections in groups of young people or medical workers. Source: First Financial Editor: Yang Zeyu ufe63 nf6036
Considering that the availability and use of test kits will increase over time, the paper said that great care should be taken in explaining the rate of case growth in January.
The paper also reminds that the urgent next steps include determining the most effective control measures to reduce communication within the community. With more understanding of the epidemiological characteristics and the dynamic mechanism of the case onset, the definition of the work case also needs to be improved. At the same time, cases need to continue to be monitored to detect any changes in epidemiology, for example, infections in groups of young people or medical workers.