(Combat New Coronary Pneumonia) What does it mean to report a new asymptomatic infection for the first time?

China News Agency, Beijing, April 1st: What does it mean for the first time to report new asymptomatic infections?

Author Zhang Su Guo Chaokai

130 new cases were added on the day, and 2 cases were confirmed on that day; 70% of the asymptomatic infections still under medical observation were in Hubei ... The National Health Committee of China first reported the asymptomatic infections of the new crown virus on April 1. Reporting, outcomes and management.

"In terms of prevention and control, it is of positive significance to report the addition of asymptomatic infections." Wang Guiqiang, director of the Department of Infectious Diseases, Peking University First Hospital, said in an interview with a reporter from China News Agency that this will prompt all parties to pay attention to screening for asymptomatic infections. In addition, the public itself will strengthen the awareness of active detection.

In fact, the Central Leading Group Meeting on New Coronary Pneumonia Epidemic on March 30 pointed out that “emphasis must be placed on monitoring, tracking, isolation, and treatment of asymptomatic infections”, and the National Health and Medical Commission issued on the 31st the “Asymptomatic Infection of New Coronaviruses” Questions and Answers on the Prevention and Control of Individuals ", Wuhan Health and Medical Commission on the 23rd to provide a unified response to the asymptomatic infection of concern to the public, it is not difficult to see that relevant departments have included asymptomatic infection in the focus of epidemic prevention. In the past few days, members of the Chinese Academy of Engineering Zhong Nanshan, Chinese Academy of Engineering Li Lanjuan, Shanghai New Crown Pneumonia Medical Treatment Expert Team Leader Zhang Wenhong, National Health and Health Committee Expert Group Member Jiang Rongmeng, and many other industry professionals have also spoke out on the prevention and control of asymptomatic infection.

According to the official definition, asymptomatic patients with neocoronavirus infection are those who have no relevant clinical symptoms, such as fever, cough, and sore throat, which are self-perceivable or clinically recognizable symptoms and signs, but positive for the pathogenic test of neocoronavirus in respiratory specimens. As of March 31, 1,367 cases of asymptomatic infection were still under medical observation.

This number is not very significant compared to the current cumulative confirmed cases (81554 cases). Why is it so concerned? A comprehensive view of the experts' views is mainly based on three aspects.

First, "difficult to prevent." Open guns are easy to hide, and dark arrows are difficult to prevent. The number of basic infections of the new coronavirus R0 is high, and those with asymptomatic infection with concealed characteristics are also contagious, so extra attention is needed. From the current four main ways to find asymptomatic infection, "full coverage" cannot be achieved.

Wang Guiqiang also analyzed this reporter that the currently notified asymptomatic infection was screened out based on active detection, and the patient was originally isolated, and the risk of transmission was relatively small. It is unclear how much more potential risk is the number of unpublished asymptomatic infections.

Second, "unknown". Due to differences in the definition of asymptomatic infection, the numbers and proportions of Chinese and foreign scientific research teams are not consistent, with different conclusions such as 1.2%, 17.9%, 18% to 31%, 30% to 60%. The length of infection, the degree of infectivity, and the mode of transmission of asymptomatic infection are unclear.

Experts from Ningbo Centers for Disease Control and Prevention compared the infection rate of close contacts of confirmed cases (6.30%) with that of close contacts of asymptomatic infections (4.11%), and concluded that "the difference in infection rates was not statistically significant" . However, Zeng Guang, chief scientist of epidemiology at the Chinese Center for Disease Control and Prevention, told reporters from the China News Agency that the sample size of this study is small and "it is not rush to draw conclusions".

Third, "Frequently." Dezhou, Guizhou, Guizhou, Mianyang, Sichuan, and other places have reported asymptomatic infections imported overseas. The Wuhan Health and Medical Commission notified a 16-year-old British student who returned to China from asymptomatic infection to a confirmed diagnosis on April 1. Local confirmed cases of asymptomatic infections in Jiaxing, Zhejiang, Henan, and other places ... Experts have pointed out that although the domestic epidemic has been basically blocked, asymptomatic infections are a potential source of infection, and whether the place is open or not The key measure of population density must be grasped. Recently, the landmark of the Oriental Pearl Tower in Shanghai was temporarily closed again, and entertainment venues such as Internet cafes and movie theaters were temporarily closed again.

Looking at the experts' point of view, it is necessary to pay attention to asymptomatic patients and not to worry too much that it will prevent the domestic epidemic from improving. To effectively prevent and control "latent people", we might as well "appropriate remedies" from three aspects.

First, make the right decisions. Zhang Wenhong wrote that the risk of large-scale community transmission of asymptomatic infected persons in China is still low, and that of asymptomatic infected persons imported into China from abroad, if not strictly screened and tracked, the risk of community transmission is greater. He put forward corresponding countermeasures: strengthen the isolation and testing of all close contacts of confirmed patients in China, and trace the source; for the immigrants, implement centralized isolation for two weeks and perform nucleic acid testing at the same time.

Li Lanjuan reminded that the detection of asymptomatic infection should be strengthened in the contact investigation, especially those with contact history with the patients in the epidemic area, "we must let them take the initiative to report and do a good job of testing, and isolate and treat them in time."

Second, precision protection. Experts recommend that you pay attention to self-monitoring and do not ignore any discomfort such as cough, fatigue, and sore throat; strengthen self-protection, wear masks and avoid risks in the complex environment of crowd gathering; create an "active" environment, such as considering selling new crowns in drug stores Virus detection test strips make it easy for the public to perform virus detection.

Finally, follow up accurately. The World Health Organization recommends clarifying the difference between asymptomatic and presymptomatic infections. Lu Shan, a professor at the University of Massachusetts School of Medicine in the United States, confirmed that infected people are indeed asymptomatic, and false positives of testing methods, cross-contamination in sample collection and testing, and data reproducibility need to be ruled out.

According to the requirements of the National Health Commission, all types of medical and health institutions at all levels should report asymptomatic infections within 2 hours. Li Lanjuan believes that big data can be used to identify potential asymptomatic infections. Some experts also mentioned that informatization reform of related systems will minimize information asymmetry and eliminate "potential risks" as quickly as possible. (Finish)