Chinanews client Beijing April 3 (Lang Lang) New crown pneumonia is sweeping the world, and the epidemic situation in China has also shown new characteristics. The epidemic prevention and control has entered a new stage of "external defense input, internal defense rebound".

Recently, the topic of asymptomatic infection has attracted much public opinion, and many people worry about how to prevent and control the "invisible threat".

In the past few days, from national requirements to local deployment, upgraded prevention and control measures for asymptomatic infected persons have been released.

Data map: Medical personnel perform nucleic acid testing on samples of returnees. Photo by Wei Liang

How dangerous is "invisible danger"?

Infectious power is equivalent to 1/3 of confirmed cases

According to the data released by the National Health and Medical Commission on April 2, as of 14:00 on April 1, 31 provinces (autonomous regions, municipalities) and the Xinjiang Production and Construction Corps reported 55 new cases of asymptomatic infection, of which asymptomatic infection was imported from abroad. There were 17 cases. 1,075 cases of asymptomatic infection are still under medical observation (226 cases imported from abroad).

This is the second day in a row that the National Health and Health Commission reported the situation of asymptomatic infected persons in the daily epidemic notification.

In response to recent public opinion on asymptomatic infections, the National Health and Medical Commission issued "Answers on the prevention and control of asymptomatic infections of new coronaviruses" on March 31, and from April 1, in the epidemic notification Publication of reports, outcomes and management of asymptomatic infections.

In addition to the national level, provincial health committees at various levels have also begun to announce the status of asymptomatic infections.

According to the data published in various places, about 70% of the asymptomatic infections (1,075 cases nationwide and 721 cases in Hubei) are still under medical observation in Hubei.

According to the questions and answers issued by the National Health Commission, the knowledge of asymptomatic infection is currently limited. At the present stage of research, it is believed that asymptomatic infection is contagious, but the length of infectious period, the degree of infectivity, and the mode of transmission need to be further studied.

Some experts believe that in view of asymptomatic infection, respiratory nucleic acid specimens can detect pathogenic nucleic acids, but because there are no clinical symptoms such as coughing and sneezing, the chance of pathogens excreting from the body to cause transmission is relatively less than that of confirmed cases.

"Ningbo Center for Disease Control recently researched that from the individual level, the transmission efficiency of asymptomatic infection is equivalent to about one third of the confirmed cases." At the State Council Joint Prevention and Control Press Conference held on April 2, Introduction to Wu Zunyou, chief expert of epidemiology, Chinese Center for Disease Control and Prevention.

Wu Zunyou said that at the group level, cases transmitted by asymptomatic infections accounted for only 4.4% of the total number of cases, and less than 5%. Asymptomatic infections have a smaller impact on the spread of the epidemic.

He reminded that all asymptomatic infections must have had a history of contact with confirmed patients, or he had been to an endemic area where an epidemic is happening. For areas where the epidemic has occurred but confirmed cases have cleared for more than two weeks, it will not Sudden asymptomatic infection suddenly appears for no reason.

Data map: During the epidemic, Henan grassroots communities strengthened quarantine prevention and control. Photo by Han Zhangyun

Central deployment and local deployment

Comprehensive upgrade of prevention and control measures for asymptomatic patients

Recently, the Central Leading Group Meeting on New Coronary Pneumonia Epidemic Situation raised the issue of prevention and control of asymptomatic infections many times.

The Central Leadership Group Meeting on New Coronary Pneumonia Epidemic Situation on April 2 pointed out the need to strengthen the management of asymptomatic infection. Efforts should be made to carry out scientific investigations of asymptomatic infections to provide scientific support for prevention and control.

At the local level, prevention and control measures have been stepped up in various places in recent years, and prevention and control of asymptomatic infections has been comprehensively upgraded in terms of investigation, timely reporting, and strict isolation.

"Scientifically identified asymptomatic infections should be based on the facts." In terms of investigation and monitoring, Henan, Hainan, and other places require increased screening of asymptomatic infections, and the scope of detection should be further expanded to new coronary pneumonia cases and found asymptomatic infections. Close contacts, key regions and groups with special requirements. Carry out investigations and epidemiological analysis of asymptomatic infections to prevent new infections and cluster sexual transmission.

It is worth mentioning that, after three cases of asymptomatic infection occurred, on March 31, Yi County, Henan announced that the villages and villages in the county were closed, and all personnel were allowed to enter and leave, except for supermarkets, hospitals, farmers' markets, etc. Suspend business.

In terms of reporting the epidemic situation, according to the requirements of the National Health and Medical Commission, Guangdong, Fujian and other places require the CDCs at all levels to report the asymptomatic infection to the network directly within two hours; quickly conduct the flow adjustment and report the asymptomatic infection. It is necessary to complete the case investigation and register the close contacts in a timely manner within 24 hours, and report the case investigation report in a timely manner.

In terms of quarantine management, Hainan and Zhejiang have launched "14 + 14" days of quarantine for asymptomatic infections.

"All patients with asymptomatic infection are strictly in accordance with the control requirements for confirmed cases." Once asymptomatic infection was found, they were immediately admitted to the designated hospital for 14 days of centralized isolation medical observation; the expiration period must be negative for two consecutive specimens for nucleic acid testing, and the sampling interval should be greater than 24 hours. After the isolation of the designated hospital, refer to the management requirements for the recovery period of confirmed cases, and then transfer to the centralized isolation point to continue observation for 14 days.

In addition, Fujian also requires 14 days of quarantine management and health monitoring to be conducted after the quarantine is lifted, and follow-up visits and follow-up visits to designated hospitals in the second and fourth weeks.

Data map: On March 13, medical staff at the Balingqiao Community Health Service Center in Xinghualing District, Taiyuan City, Shanxi Province, viewed the throat swab samples taken by returning workers. Photo by China News Agency reporter Wei Liang

Pay attention, but do n’t be nervous

How to prevent "asymptomatic infection"?

The existence of asymptomatic infections has caused many people to worry: how to prevent and control "hidden danger"?

"Asymptomatic infections are relatively common in infectious diseases. We must pay attention to this, but we must not over-interpret it." Zhang Wenhong, director of the Department of Infectious Diseases, Huashan Hospital, Fudan University, said recently.

Zhang Wenhong said that to prevent symptomatic and asymptomatic infections, there is no difference in the precautionary measures taken by healthy people. "No matter what time, we still need to be vigilant. Until the global epidemic is not over, we must maintain good hygiene habits, wear masks, wash hands and keep social distance when necessary. I think these methods should be for everyone. It can be sustained for a long time. "

Regarding the infectivity of the virus carried by asymptomatic patients, Wu Zunyou said in a video interview with Xinwang on April 1 that the infectivity of infected people depends on the amount of the virus. Large, no symptoms appear, and it is also related to a small amount of virus. If the amount of virus is small, the risk of transmission will be small.

"We have a complete set of prevention and control measures, even if there are asymptomatic infections, they are still under control, and even if there are individual ones, they will not cause transmission and spread," he said.

For the investigation of asymptomatic infection, Li Lanjuan, an academician of the Chinese Academy of Engineering, believes that the detection of asymptomatic infection should be strengthened in the investigation of contact, especially those with contact history with patients in the epidemic area. Timely isolation and treatment. "

In addition to the investigation of asymptomatic infections, experts recommend that the public pay attention to self-monitoring and do not ignore any discomfort such as cough, fatigue, and sore throat; to strengthen self-protection, wear masks and avoid risks in the complex environment of crowd gathering ; Create a "proactive" environment, such as considering selling test strips of new crown virus detection in pharmacies to make it easier for the public to perform virus testing. (Finish)