Gao Fu, director of China CDC, responded to the controversial paper: everyone didn’t understand it, confusing the paper with clinical diagnosis.
WeChat official account News of CBN WeChat, the critical moment of COVID-19 epidemic prevention and control, a paper published in the New England Journal of Medicine, pushed the China Center for Disease Control and Prevention (hereinafter referred to as "China CDC") to the forefront.
The reason is that, according to this paper, research shows that interpersonal communication has occurred between close contacts since mid-December 2019. In addition, from January 1 to January 11, a total of 7 medical staff were infected. But at this time, the public knew nothing about it.
Should scientists publish papers first or prevent them first? The focus of controversy comes from this. On the morning of January 31st, CBN reporter interviewed Gao Fu, a member of the National Health Commission high-level expert group and director of China CDC. He is the co-author of the above paper.
"This is a retrospective analysis! In mid-December, I still don’t know what the disease is, and the pathogen is unclear. It is the inference of investigating more than 400 cases of epidemiology! Onset’s days are all speculation, which everyone didn’t understand! Mix epidemiological investigation with clinical diagnosis. " Gao Fu told CBN.
Gao Fu also said that retrospective investigation is one of the responsibilities of CDC, to find the culprit, retrospective investigation, and guide future prevention and control. "Our prevention and control has never stopped, and everyone has not slept for a month."
This is a retrospective analysis.
This paper, published on January 29th, US time, was led by China CDC, including professionals from Hubei CDC and Hong Kong University. Correspondents of the study include Feng Zijian, deputy director of China CDC, and Yang Bo, director of Hubei CDC. Co-authors also include Gao Fu.
In this paper, the investigation team analyzed the reported 425 laboratory-confirmed cases as of January 22, 2020. Analysis shows that among the first 425 confirmed patients, the median age is 59 years old and the male is 56%. Most cases (55%) occurred before January 1, 2020 were related to the seafood wholesale market in South China, and the subsequent cases were 8.6%. The average incubation period was 5.2 days, and the 95th percentile of the distribution was 12.5 days. In the early stage, the scale of epidemic cases doubled every 7.4 days, the average continuous interval of infection was 7.5 days, and the number of basic infections (R0) was estimated to be 2.2.
According to this information, the paper said that there is evidence that interpersonal communication has occurred between close contacts since mid-December 2019.
This paper reveals more information about the epidemic situation in COVID-19, which has aroused widespread doubts.
On January 31st, China CDC published an article entitled "Notes of China Center for Disease Control and Prevention on Publishing Articles in the New England Journal of Medicine". The article stated that the paper was based on a retrospective analysis of 425 confirmed cases (including 15 medical staff) reported as of January 23rd, 2020, and all cases were published to the public before the paper was written. The 15 cases of medical staff infection mentioned in the paper were announced to the public by Academician Zhong Nanshan, the leader of the high-level expert group in National Health Commission, on the evening of January 20th and the Wuhan Health and Health Commission in the early morning of January 21st.
The viewpoint that "interpersonal communication occurred among close contacts in December 2019" put forward in this paper is a retrospective inference based on the epidemiological investigation data of 425 cases.
The article also said that publishing the survey results in academic journals in time will help professional colleagues at home and abroad to understand the characteristics of the disease in time, jointly evaluate and judge the epidemic situation, and improve the prevention and control strategies.
However, this article did not respond, when did China CDC come to the judgment that "interpersonal communication occurred among close contacts in December 2019".
For infectious epidemiology, retrospective study is indeed extremely important. Without retrospective study, it is impossible to understand the incidence of infectious diseases more clearly and then formulate prevention and control strategies for infectious diseases. Therefore, after the outbreak of an infectious disease and case diagnosis, epidemiological investigators will appear first.
An expert in epidemic virology also told reporters that retrospective research is the basic work of infectious diseases and must be carried out according to existing cases. Without cases, no one can observe what the development path of this virus is.
"In fact, the data of 425 cases is not enough to show the characteristics of the new virus. It can only explain the situation in the past and (425 cases) at that time. How to develop in the future needs to continue to be observed." The above-mentioned experts in epidemic virology said.
For example, China CDC stated that these cases were previously confirmed cases, and the research team used these public data to start a retrospective analysis.
How to carry out retrospective analysis?
According to this paper, the earliest cases in COVID-19 were identified through the surveillance mechanism of pneumonia with unknown etiology.
In order to identify pneumonia cases and strive to improve the sensitivity of early detection, the research team developed a tailor-made monitoring program to identify potential cases on January 3, 2020.
The initial working case definition for suspicious COVID-19 is based on the case definition of SARS and Middle East Respiratory Syndrome (MERS). After obtaining new information about confirmed cases, the epidemiological criteria for defining suspicious cases were updated on January 18, 2020.
Once suspicious cases are found, a joint team composed of China CDC, provincial CDC, local CDC and county CDC will be notified to carry out detailed on-site investigation and collect respiratory tract samples, which will be tested in the Center for Viral Disease Prevention and Control of China CDC.
A joint team composed of staff from China CDC and local CDC also conducted detailed field investigations on all suspected and confirmed cases. They collected epidemiological data through interviews with infected people, relatives, close contacts and medical staff, so as to determine the contact history of patients two weeks before onset, including the date, frequency, frequency and mode of contact with wild animals, especially the wild animals available in the South China Seafood Market in Wuhan. In addition, the researchers also collected information about exposure to any relevant environment and contact with others with similar symptoms.
All the epidemiological information collected in the survey, including contact history, timetable and the identity of close contacts, were cross-checked.
Through this path, the research team obtained the epidemiological information of 425 cases.
The basic infection number is about 2.2.
The importance of retrospective analysis of infectious diseases lies in seeing clearly the laws of infectious diseases, and only by seeing clearly the enemy can we make better prevention and control.
In addition to the above-mentioned questioned contents, what other noteworthy information does this paper reveal?
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.
According to the paper, limited to the data before January 4th, it is estimated that the basic number of infections in COVID-19 is about 2.2, which means that each patient spreads the infection to 2.2 other people on average. As far as COVID-19 is concerned, the paper said that the control challenges include the obvious existence of many mild infections and the limited resources to isolate cases and close contacts.
However, due to the increased awareness of the epidemic situation and the increased availability and utilization rate of inspections in recent weeks, the confirmed infection rate will increase.
A chart used in this article shows that after January 11th, the number of cases decreased. However, the paper also said that it is probably due to the uncertainty of recent cases and the delay in identification and reporting, rather than the real turning point of incidence.
Considering that the availability and usage of test kits will increase with the passage of time, the paper said that extra care should be taken in explaining the growth rate of cases in January.
In short, the research results also show that in the early stage, the case size doubled every 7.4 days. The average continuous interval is 7.5 days.
The paper also reminds that the urgent next step includes determining the most effective control measures to reduce the spread within the community. With a better understanding of epidemiological characteristics and the dynamic mechanism of cases, it is also necessary to improve the definition of work cases. At the same time, it is also necessary to continue to monitor cases to find any changes in epidemiology, such as infections among young people or medical workers.
Original title: Gao Fu responded to the paper’s query: everyone didn’t understand, confusing the paper with clinical diagnosis.
[Disclaimer] The texts, pictures, audio and video that are not marked with "Source: Upstream News-chongqing morning post" or "Upstream News LOGO" on the upstream news client are all reposted. If the reposted manuscript involves copyright issues, please contact the upstream news.