On March 26, Premier Li Keqiang presided over a meeting of the Central Working Leadership Group on Responding to the New Crown Pneumonia Epidemic, emphasizing that “great importance should be attached to the prevention and treatment of asymptomatic infected persons.” from April 1, the first official notification of daily asymptomatic infected person reports, management. On April 1, the National Health Commission reported data showing that on March 31, 31 provinces (autonomous regions and municipalities directly under the central government) and the Xinjiang Production and Construction Corps reported 130 new cases of asymptomatic infected persons, 2 cases were converted to confirmed cases that day, and 302 cases were released from quarantine that day. Still under medical observation asymptomatic infected 1367 cases, 174 cases less than the previous day. Previously, the official website of the National Health Commission released “Questions and Answers on Prevention and Control of New Coronavirus Asymptomatic Infected Persons” on March 31, disclosing that as of 24:00 on March 30, there were 1,541 cases of asymptomatic infected persons under medical observation, of which 205 cases were imported from abroad. The development of the new crown epidemic so far has basically passed the period of rapid growth of confirmed cases. Compared with confirmed cases, how to prevent and control the more insidious asymptomatic infected people has become the current focus and difficulty, as well as the controlling project of the epidemic blockade at this stage. April 1, well-known virology experts, the University of Hong Kong School of Medicine Professor of Biochemistry Jin Dongyan said in an interview with Red Star News reporter, the emergence of asymptomatic infected with the characteristics of the virus itself, the infected person infected with the pathway, infected with the amount of the virus, as well as the patient’s own immune characteristics are related. Now the proportion of asymptomatic infected people is not clear, how many asymptomatic infected people with a high degree of infectiousness is not clear, foreign research can only be used for reference, the country has strengthened the management of asymptomatic infected people, the next step is to figure out these situations. At the same time, a number of experts also said that although asymptomatic infected people have a lower risk of causing infectious outbreaks, but need to pay high attention to asymptomatic infected people. What leads to the emergence of asymptomatic infected people? Experts: may be related to the patient’s autoimmune characteristics According to the official website of the National Health Commission, “Questions and Answers on the Prevention and Control of New Coronavirus Asymptomatic Infected Persons”, new coronavirus asymptomatic infected persons (hereinafter referred to as asymptomatic infected persons) refers to people who do not have relevant clinical symptoms, such as fever, cough, sore throat and other self-presenting or clinically recognizable signs and symptoms, but respiratory specimens and other specimens of the new coronavirus etiology testing positive people. Positive. Asymptomatic infections can be divided into two situations: first, the infected person is positive for nucleic acid test, after 14 days of observation of the incubation period, there are no self-perceived or clinically recognizable signs and symptoms, always asymptomatic infection; second, the infected person is positive for nucleic acid test, there are no self-perceived or clinically recognizable signs and symptoms at the time of sampling, but then a certain clinical manifestation occurs, i.e., the incubation period of the “asymptomatic infection”. “Asymptomatic infection”. What leads to the emergence of asymptomatic infections? Well-known virology experts, the University of Hong Kong School of Medicine Professor of Biochemistry Jin Dongyan told Red Star News reporter, the emergence of asymptomatic infected people, the first may be related to the characteristics of the virus itself, the second may be related to the pathway of the patient’s infection and the amount of infected virus. Jin Dongyan explained, because the virus in the wild host, such as the new coronavirus in the bat does not show symptoms, such as MERS virus in the camel pathogenicity is very low. This can happen in bats, camels and also in humans. In fact, all four coronaviruses that have existed in the past that can infect humans are the ones that can only cause the common cold in humans. So the emergence of asymptomatic infected people with the new coronavirus is related to the characteristics of the virus itself, which is not a very unusual phenomenon. “For the patients themselves, the emergence of asymptomatic infected people may also have something to do with the patient’s own immune situation.” Jin Dongyan continued to explain, “because the patient’s symptoms are mainly caused by the immune response, if the virus does not provoke the patient’s immune response will not show symptoms”, “a situation is that if the patient’s immune response is very strong, the immune system can suppress most of the virus, but at the same time has not yet completely removed the virus , it may manifest as asymptomatic. Another situation is that if the patient’s immune deficiency or immune suppression, then the patient is less likely to show symptoms.” The characteristics of the patient’s immune system can cause the immune response to the virus to uncouple, or decouple, from the replication of the virus, Kim Dongyan said. So much so that the patient’s body has a high viral load or no symptoms. This is the patient’s autoimmune characteristics lead to asymptomatic situation. Jin Dongyan believes that the proportion of asymptomatic infected people with the new coronavirus is higher than that of SARS and MERS. How high is the proportion of asymptomatic infected people? There are differences between countries, the proportion of China in mid-February about 1.6% How high is the proportion of asymptomatic infected people? In early March, the National Health Construction Commission released the “China-WHO Expert Group Joint Inspection Report” mentioned that there have been reports of asymptomatic infections, but most of the cases that were asymptomatic at the time of the report will subsequently develop symptoms, the true proportion of asymptomatic infections is not yet clear, but it is relatively rare. According to a study by a team from Wu Tangchun, dean of the School of Public Health at Huazhong University of Science and Technology (HUST), the research team analyzed data on 25,916 laboratory-confirmed cases of new coronary pneumonia in the Wuhan Municipal Health Commission’s Statutory Infectious Disease Reporting System as of Feb. 18 through component modeling. At least 59 percent of infections in Wuhan are predicted to be undetected, which may include asymptomatic and mildly symptomatic cases. In a previous interview with China News Weekly Wu Tangchun said the results were predicted by his team based on the most conservative modeling and that no actual epidemiological investigation had been conducted. In addition, a large-scale flow-control paper published in the Chinese Journal of Epidemiology by the CDC’s Epidemiology Group on Feb. 17 mentioned that as of Feb. 11 the CDC had received a total of 72,314 reported cases in the country, containing 889 cases of asymptomatic infections, a proportion of about 1.6 percent. According to Caixin.com, a study of 565 Japanese citizens who were in a car from Wuhan in early February showed that four of the 13 infected evacuees, or 31 percent, showed no symptoms. The Hunan CDC article, published March 6 in Practical Preventive Medicine, had painted a picture of such people. The study looked back at 36 cases of asymptomatic infections in the province from Jan. 1 to Feb. 8 and found that asymptomatic infections stood at 4.05 percent of those who tested positive. A report in the Financial Times showed that Italy had tested all 3,300 people in the town of Vaud, near Venice, for nucleic acid in late February, and that about half of the carriers in the 3 percent of the infected population were asymptomatic.On March 25, the ECDC updated again that many of the reported asymptomatic cases had become symptomatic later in the course of the infection. On March 16, Iceland, with a population of just over 360,000, completed testing 3,787 people for the new coronavirus, with an average of less than one in a hundred having been tested, and 218 of them coming back positive. Thorolfur Gu?nason, the Icelandic government’s chief epidemiologist, revealed in an interview with U.S. media outlet BuzzFeed that about half of those who tested positive were asymptomatic, while the other half had mild flu-like symptoms. According to the Southern Metropolis Daily’s compilation of related reports, Iceland’s asymptomatic rate is about 50 percent, Italy’s is about 44 percent, South Korea’s is 20 percent, and Japan’s is 0.06 percent. Why is the proportion of asymptomatic infections so different from region to region? According to Jin Dongyan, studies of asymptomatic people are still small samples. The study of asymptomatic infected people in a range will be affected by many factors, such as the local infection rate, the proportion of mild disease, and so on. Some people with mild cases who have not yet sought medical attention may affect the proportion of asymptomatic people, so at present these studies can only be used as a reference. The country currently includes asymptomatic infected people in the management and daily notification, the next step is to figure out the proportion of this part. Jin Dongyan also suggested that we can’t stop at figuring out the proportion of asymptomatic people, but also figure out what proportion of asymptomatic patients with high viral loads are actually infected. Will asymptomatic infected people cause the spread of transmission? The risk is low, but of high concern Are asymptomatic infected people infectious? Previously, Wang Guangfa, a member of the National Health Commission’s expert group and director of the Department of Respiratory and Critical Care Medicine at Peking University First Hospital, suggested in an interview with Red Star News that asymptomatic infected people and patients with mild illnesses may not detoxify as much as patients with severe illnesses, so they are relatively less infectious. In the final inspection report of the China-WHO joint expert group, in which Wang Guangfa participated, it was also mentioned that asymptomatic infected people are not the main driver of virus transmission. On March 27, academician Zhong Nanshan said in an interview with a CCTV reporter, on how to control the epidemic, not only focus on symptomatic people, but also pay special attention to asymptomatic close contacts of diagnosed patients, which China attaches great importance to. About China’s domestic “asymptomatic infected people” situation, the current understanding is very limited, there is no specific figures, there is no detailed study. However, based on the known facts, some inferences can be made. For example, while asymptomatic infections generally have a high rate of transmission to close contacts, the number of new cases of C.pneumonia in China has recently been declining rather than rising. This suggests that China does not yet have a large number of “asymptomatic infections”. On March 31, Zhang Wenhong, head of Shanghai’s new coronavirus medical treatment expert group, wrote in an article on his team’s “Huashan Infection” that a healthy person infected with the coronavirus will eventually have both “symptomatic” and “asymptomatic” states. Asymptomatic”. The exact proportions of these two states are shown in some current studies, for example, the proportion of people infected with the new coronavirus who are asymptomatic ranges from about 18-31%. If the number of confirmed cases is small, the number of asymptomatic infections must also be small. In this case, the risk of transmission from asymptomatic infections in the country is low. At present, the number of new cases in the country has dropped to a very low level, and the number of cases of asymptomatic infected persons is certainly not very high. As long as the country strengthens the isolation and testing of all the close contacts of confirmed patients and does a good job of traceability, the risk of transmission in the community will be reduced. At this stage, asymptomatic people in China are mainly detected through four ways: medical observation of close contacts, investigation of outbreaks, tracing of the source of infection, and testing of people with a history of traveling or living in areas where some of the new cases of C.pneumonia continue to spread both within and outside the country. Do asymptomatic infected persons need treatment? Do not need special treatment need supportive treatment How to manage the asymptomatic infected person?On March 30, accepting the CCTV News 1 +1 interview Li Lanjuan academician said that because the asymptomatic infected person itself is contagious, so we must pay great attention to this problem. So it must be detected early, the main means is to carry out testing, especially for those who have had a history of contact with the infected area, the patient contact history of this category of people. In addition, we hope that these people can take the initiative to report, so that early detection can be carried out, timely isolation and treatment, so as not to cause further infection to other people. In addition, Li Lanjuan said that it can also be discovered through big data. Some people may not know if they have a history of exposure, which requires the use of big data to find them out and test them as early as possible. The NHSC included asymptomatic infected persons with novel coronavirus in the prevention and control management in the Prevention and Control Program for Pneumonia Infected by New Coronavirus (Third Edition), which was released on January 28, and all subsequent revisions put forward clear and specific requirements for the reporting and management of asymptomatic infected persons. All levels and types of medical and health institutions should report directly to the network within two hours of discovering asymptomatic infected persons. After receiving the report of asymptomatic infected persons, the county (district) level CDC organizations should complete the case investigation within 24 hours, register the close contacts in a timely manner, and report the case investigation form or investigation report through the infectious disease reporting management information system in a timely manner. Asymptomatic infected persons should be centrally isolated for 14 days, and in principle, those who have been centrally isolated for 14 days and whose nucleic acid tests of two consecutive specimens are negative (with a sampling interval of at least 24 hours) can be released from isolation; if the nucleic acid test is still positive, the person will continue to be isolated for medical observation. If clinical manifestations occur during isolation for medical observation, the case should be promptly transferred to a confirmed case for standardized treatment. Close contacts of asymptomatic infected persons are also subject to 14 days of centralized isolation for medical observation. At the State Council’s Joint Prevention and Control Mechanism press conference on March 24, Wu Zunyou, a researcher at the CDC, said that because China takes isolation and observation measures for close contacts, once symptoms appear, they are all transferred to hospitals for treatment, which will not result in social transmission. However, the risk of asymptomatic infected people to cause great concern, the issue is being closely watched. So asymptomatic infected people need treatment? Jin Dongyan told Red Star News reporter, for mild and asymptomatic infected people, the new coronavirus infection is a self-limiting disease does not require special treatment, only some supportive treatment is enough. The current situation faced by some places is to prioritize to ensure that symptomatic diagnosed patients receive medical treatment. But is it possible to give antiviral drugs to asymptomatic infected people to shorten the time it takes for them to turn negative? Jin Dongyan said that because patients are already asymptomatic, there is still a question mark over whether it makes sense to give them the drugs. Some antiviral drugs may speed up conversion. But if the patient is asymptomatic, and there is no special reason, do not treat the patient specifically. Source: Chengdu Business News