130 new cases were added one day and 2 cases were confirmed on the same day; Seventy percent of asymptomatic infections still under medical observation are in Hubei & hellip& hellip; The national health and Health Committee of China announced the first report, outcome and management of asymptomatic infections in COVID-19 in April 1st.
"In terms of prevention and control, it is of positive significance to report new asymptomatic infections." Wang GuiQiang, director of the Department of infectious diseases of the first hospital of Peking University, told China news agency that this will urge all parties to pay attention to screening asymptomatic infected people, and the public itself will strengthen the awareness of active detection.
The picture shows a citizen handling business on a self-service gas vending machine. Photographed by China News Agency reporter Shi Xiaojie
What is' asymptomatic '?
In fact, novel coronavirus pneumonia epidemic prevention working group meeting in March 30th pointed out that "we must emphasize the good monitoring, tracking, isolation and treatment of asymptomatic infections". The national health and Health Committee issued the 31 question and answer on prevention and control of asymptomatic infections in New Coronavirus, and the Wuhan Health Protection Committee on 23 th gave a unified reply on the asymptomatic infected people. It is not difficult to see that relevant departments have included asymptomatic infected persons in the focus of epidemic prevention.
China novel coronavirus pneumonia Zhong Nanshan, China Academy of Engineering academician Li Lanjuan, Shanghai new crown pneumonia medical treatment team leader Zhang Wenhong, national health protection committee expert group Jiang Rongmeng, and many other industry insiders have been vocal control of asymptomatic infections.
According to official definitions, asymptomatic COVID-19 infected persons are non related clinical symptoms, such as fever, cough, sore throat and other symptoms or signs that can be self perceived or clinically recognizable. But respiratory tract specimens are positive for COVID-19 etiological tests. As of March 31, 1367 cases of asymptomatic infection were still under medical observation.
The picture shows people wearing masks on the subway. Photographed by China News Agency reporter Wang Zhongju
Why are asymptomatic infected people so concerned?
The number of '1367 cases' is not very prominent compared with the current cumulative confirmed cases (81554 cases). Why is it so concerned? Taking a comprehensive view, the experts' views are mainly based on three aspects.
First, 'hard to prevent'.
An open gun is easy to hide, but an arrow in the dark is hard to defend. COVID-19's basic contagious number R0 is high, and the asymptomatic infection with concealed features is also contagious. Therefore, special attention should be paid to it. From the current four main ways to find asymptomatic infected people, it is impossible to achieve 'full coverage'.
Wang GuiQiang also told our reporter that the asymptomatic infected persons reported at present are screened out according to active detection. The patients are already in isolation, and their transmission risk is small. More potential risks, that is, the number of unpublished asymptomatic infections, are unclear.
Due to differences in the definition of asymptomatic infection, the number and proportion of Chinese and foreign scientific research teams are inconsistent, with different conclusions such as 1.2%, 17.9%, 18% to 31% and 30% to 60%. The length of infection period, infectious strength and mode of transmission of asymptomatic infected persons are also unclear.
Experts from Ningbo Center for Disease Control and prevention compared the infection rate of close contacts of confirmed cases (6.30%) with that of asymptomatic infected persons (4.11%), and concluded that there was no significant difference in infection rate. However, Zeng Guang, chief epidemiologist of China Center for Disease Control and prevention, told China news agency that the sample size of this study is small and "we can't rush to draw a conclusion".
Dezhou, Shandong, Guiyang, Guizhou, Mianyang, Sichuan and other places have reported the import of asymptomatic infections abroad. On April 1, Wuhan Health Commission reported that a 16-year-old British student returning to China had changed from asymptomatic infection to diagnosis. In Jiaxing, Zhejiang Province and Luohe, Henan Province, there were asymptomatic infections associated with locally confirmed cases & hellip& hellip;
According to this, experts pointed out that although the spread of the domestic epidemic has been basically blocked, the key yardstick of population density must be mastered to judge whether the place is open or not because asymptomatic infected persons are the potential source of infection.
Recently, Shanghai's Oriental Pearl landmark has been temporarily closed, and Internet cafes, cinemas and other entertainment venues have been temporarily closed.
Data figure: Zhang Wenhong. Photographed by China News Agency reporter Tang Yanjun
How should we treat 'asymptomatic infected people' scientifically?
Novel coronavirus pneumonia clinical group leader and Huashan Hospital Affiliated to Fudan University infection department director Zhang Wenhong said that we should pay attention to this problem but not over interpret it. This is our attitude towards treating asymptomatic cases scientifically. Zhang Wenhong said.
He said that the so-called asymptomatic infected people refer to: for example, 10 people are infected by the virus. After isolating these high-risk groups, in fact, we found that there may be only 8 people who really get sick, and there are 2 others. Some symptoms are very mild, and others may really have no symptoms.
"But in fact, this phenomenon is also common in infectious diseases," Zhang Wenhong said. He said that if there are asymptomatic 'carriers', there will certainly be another 8 people who are symptomatic.' we are not likely to see no symptomatic people in a society, and then all asymptomatic (infected people) lurk in the crowd, which is unrealistic. '
The picture shows citizens in Ezhou, Hubei Province wearing masks and riding electric vehicles. Photographed by China News Agency reporter Shi Xiaojie
How to prevent and control 'asymptomatic'?
From the perspective of experts, we should not only pay attention to asymptomatic patients, but also worry too much that they will hinder the improvement of the domestic epidemic situation. To effectively prevent and control 'lurks', we might as well' suit the remedy to the case 'from three aspects.
First of all, make accurate decisions.
Zhang Wenhong pointed out that the risk of large-scale community transmission caused by asymptomatic infected people in China is still low, while asymptomatic infected people imported from abroad to China will have a greater risk of community transmission if they are not strictly screened and tracked. He put forward corresponding countermeasures: strengthen the isolation and detection of all close contacts of diagnosed patients in China, and do a good job in tracing the source; The inbound population was isolated for two weeks and nucleic acid detection was carried out at the same time.
Li Lanjuan reminded that the detection of asymptomatic infected persons should be strengthened in the contact investigation, especially those who have a history of contact with patients in the epidemic area, 'we must let them take the initiative to report and do a good job in the detection, and isolate and treat them in time after discovery'.
Secondly, precise protection.
Experts suggest paying attention to self-monitoring and not ignoring any discomfort such as cough, fatigue and sore throat; Strengthen self-protection, wear masks and avoid risks in the complex environment where people gather; Create an active environment, such as selling COVID-19 test strips at a drugstore, so that people can easily detect viruses.
Finally, accurate tracking.
The World Health Organization recommends clarifying the difference between asymptomatic infection and pre symptomatic infection. Lu Shan, a professor at the school of medicine of the University of Massachusetts, said that if it is confirmed that the infected person is indeed asymptomatic, it is necessary to exclude false positives of test methods, cross contamination in sample collection and testing, and repeatability of data.
According to the requirements of the National Health Commission, all kinds of medical and health institutions at all levels should report asymptomatic infections online within 2 hours. Li Lanjuan believes that potential asymptomatic infections can be found through big data. Some experts also mentioned the information reform of relevant systems to eliminate information asymmetry to the greatest extent and eliminate 'potential risks' as soon as possible.