Will the 'asymptomatic infected people' who have been diagnosed with more cases be the stealth killer?
Cases of asymptomatic infection have spread the virus in some areas.
The Beijing News (Reporter Ni Wei Dai Xuan) has no fever, cough, fatigue, etc., but the positive nucleic acid test of the new crown virus shows that it has been infected. The 'asymptomatic infection' of this kind of new coronary pneumonia occurs in many places.
Today (February 10), two cases of asymptomatic infection were disclosed in Guangxi and Henan. The asymptomatic duration reached 16 days and 17 days, respectively.
The Beijing News reporter found that according to the new version of the National Health and Health Commission's new prevention and control plan, asymptomatic infections have been reduced to the scope of confirmed cases. Heilongjiang reduced 13 confirmed cases, and Shanxi also reduced one, all of whom were asymptomatic.
This does not mean that asymptomatic people are completely safe.
According to the National Health Commission, asymptomatic infections may also become a source of infection, and at the same time, some asymptomatic infections will continue to show clinical manifestations. As of now, there have been multiple incidents of asymptomatic infection in many families.
Focus 1 Why subtract “asymptomatic people” from confirmed cases?
The new version of the prevention and control program is readjusted, and the 'asymptomatic infection' category is added.
On February 9, the Heilongjiang Provincial Health and Health Commission informed that 14 cases had been subtracted from the confirmed cases the previous day, of which 13 were asymptomatic infections.
Zhao Yuhui, a second-level investigator of the Heilongjiang Health and Medical Commission's Medical Affairs and Medical Administration Department, explained that the 13 cases without any symptoms but with a positive nucleic acid test were counted as asymptomatic infection by the National Health and Medical Commission on the 8th and will no longer be counted as confirmed cases .
The reporter noticed that in the 'New Coronavirus Pneumonia Prevention and Control Plan (Fourth Edition)' issued by the National Health and Medical Commission on the 7th, positive cases of nucleic acid detection were divided into confirmed cases and asymptomatic infections, and they are no longer collectively referred to as confirmed cases. .
So far, asymptomatic infections have occurred in many places including Liaoning, Zhejiang, Shandong, Henan, Hubei, Guangdong, Shaanxi, Jilin, Heilongjiang, Hunan, Hainan, Sichuan, Chongqing, Inner Mongolia, and Guangxi.
Cases of asymptomatic transmission of the virus have also occurred in some areas.
In Cixi, Ningbo, Zhejiang, a group of 'Mahjong' playing mahjong had no contact history in Wuhan and had no contact with cases, but they were successively diagnosed. Among them, a 65-year-old woman was first infected. He then infected 'Mah You' and neighbors by playing mahjong, resulting in 4 confirmed cases and 2 asymptomatic infections.
After investigation, the old lady was infected by son-in-law. The son-in-law met with a friend who had been active in Wenzhou from January 17th to 19th and had a meal together. He was infected but did not have fever and was an asymptomatic person.
On January 27, the earliest reported case of asymptomatic infection in the country also infected his family. After a woman returned to Anyang, Henan, from Wuhan on January 10, five relatives in the family became ill and were diagnosed with new coronary pneumonia. She did not show symptoms.
Focus 2 Why do people with asymptomatic infections appear?
It is related to the degree of immune response of the infected person, and inhibits the growth of the virus before the damage is caused, and the human body does not respond significantly.
Why don't people show obvious symptoms after infection? Ding Xinmin, chief physician of the Department of Respiratory Medicine, Beijing Shijitan Hospital, analyzed that this was related to the degree of immune response of infected persons.
If the virus that invades the human body is regarded as the 'enemy' and the human immune cells are regarded as 'our army', when the virus load is low, that is, the 'enemy' is weak, and the immune cells are strong, the virus will cause greater damage. Inhibiting its growth before, or even extinguishing it quickly, the human body's response is not typical or obvious, and is considered asymptomatic.
'It is difficult to distinguish between asymptomatic or mild symptoms. Some people may have symptoms of weakness, but it is difficult to judge the infection from this.' Ding Xinmin said.
Wang Linghang, chief physician of the emergency department of infectious diseases of Beijing Ditan Hospital, believes that asymptomatic infection is not the same as 'false positive'. Finding and proposing 'asymptomatic infection' is actually a process in which we gradually recognize new things, and it is closely related to clinical detection methods.
Advances in clinical testing have provided the gold standard for diagnosis. Since January 17, nucleic acid tests have been performed in suspected cases, and PCR methods and related kits have been used to determine whether they are infected. Later, through medical observations of close contacts of confirmed patients, it was found that some nucleic acid tests were positive, but mild cases were even 'asymptomatic', which was called asymptomatic infection.
In this process, the knowledge of the disease spectrum has gradually expanded from the initial cases of pneumonia to the continuous disease spectrum of 'asymptomatic infection-mild cases-severe critical cases'.
Focus 3 Who is vulnerable to becoming asymptomatic?
It is mainly close contacts of confirmed patients, mostly family members, and those with infection are asymptomatic for 17 days.
Asymptomatic infections can also become a source of infection, as indicated by the fourth edition of the National Health Commission's prevention and control plan and the fifth edition of its treatment plan.
Li Xingwang, chief expert of the Infectious Disease Diagnosis and Research Center of Beijing Ditan Hospital, said that at present, asymptomatic infections are mainly close contacts of confirmed patients, and more often occur in family members.
On February 9, the first case of asymptomatic infection occurred in Taiwan, namely by a family member.
This is the 18th person diagnosed in Taiwan. It was the son of a couple in their 50s who had been diagnosed with New Crown Pneumonia announced on February 6. This case had no respiratory symptoms and no fever. However, after isolation and testing, it was confirmed that the test result of the new coronavirus was positive. However, after testing, it was found that the amount of virus in the body is very high, which is equivalent to that of parents. It does not rule out that subsequent symptoms will occur.
On the same day, one case of asymptomatic infection was confirmed in Changyuan, Henan Province, which was asymptomatic for 17 consecutive days.
Yuan Guoyong, a member of the high-level expert group of the National Health and Medical Commission and professor of the Department of Microbiology at the University of Hong Kong, and his colleagues published in The Lancet that asymptomatic SARS patients are rare, but in their retrospective study of SARS, Some asymptomatic SARS patients were also recorded.
Focus 4 Will people with asymptomatic infection become the 'invisible killer'?
This type of infection is less viral and has less transmission than diagnosed cases, and is not the main communicator
Will asymptomatic infections that can not be detected through body temperature testing become the 'invisible killer' in the crowd?
Both WHO and experts believe that although there have been cases of asymptomatic infection of the virus, they are generally not the main communicators and the transmission is weak.
The World Health Organization responded to this question on February 4, stating that, according to observations of the Middle East Respiratory Syndrome (MERS), transmission of other coronaviruses through asymptomatic infections is very rare. Therefore, asymptomatic infections may not be the main spreaders of the virus.
Li Xingwang explained at the press conference of the National Health and Medical Commission that asymptomatic infections occur more often in close contact with patients, especially the phenomenon of family gathering is more obvious, so there is no need to panic if you do not contact the infected people. Such close contacts have also achieved good control through isolation and medical observation. 'There is a certain correlation between the amount of virus and the severity of the disease. Asymptomatic infections are milder, and the amount of virus will be less, so the ability to transmit will be weaker than those of severely ill patients. On the other hand, the new crown pneumonia mainly through short-range droplet Spread, asymptomatic infections usually have less cough, so the spread is not very strong. '
However, patients with asymptomatic infection may also develop clinical symptoms and become confirmed patients. The fourth edition of the National Health and Construction Commission's prevention and control plan states that the reported asymptomatic infections should be corrected to “confirmed cases” if they appear clinically.
Ding Xinmin suggested that regardless of whether the infected person is 'asymptomatic', they should pay attention to rest and avoid strenuous activities. Once immunity declines, the virus may counterattack and cause infection. The human body will also initiate a stronger immune response. If the reaction is too strong, in addition to killing the virus, it may also accidentally damage normal human cells, leading to myocarditis, liver and kidney damage, and even multiple organ damage.
Focus 5 How should people with asymptomatic infection be prevented?
Pay attention to self-monitoring, pay attention to the health status of the surrounding people, and isolate if the nucleic acid test is positive
Asymptomatic infections lack obvious symptoms, are not easy to cause alertness, and some are still active, posing challenges to disease prevention and control and public protection.
How were such asymptomatic infections found?
The fourth edition of the National Health and Construction Commission's prevention and control plan revealed that asymptomatic infections were found mainly through clustered epidemic investigations and follow-up investigations of infection sources.
Sun Wei, deputy director of the Heilongjiang Provincial Center for Disease Control and Prevention, said that to find asymptomatic infected persons, frontline epidemiological investigators need to use big data platforms to work closely with grass-roots community organizations and medical and health institutions to isolate and manage close contacts. Make medical observations.
Wang Linghang believes that the public should not be overly alarmed or take it lightly.
First, pay attention to health monitoring. The so-called asymptoms, if they are closely questioned, they often still have discomfort, such as low fever and cough, but they have not affected life. Still pay attention to self-monitoring, pay attention to the health status of the surrounding people.
Secondly, in the complex environment where people gather, adequate respiratory protection should be done. The spread of the virus is related to the speed of airflow and the amount of secretions. Be vigilant when someone coughs. If you talk closely without a mask, there may be risks.
Zhong Nanshan, a high-level expert group leader of the National Health and Medical Commission and an academician of the Chinese Academy of Engineering, also said in an interview that there are not many asymptomatic infections, and that most of them have been in contact with confirmed patients or have a history of exposure in Wuhan. There are reports that some asymptomatic infections can be cured by themselves, and some asymptomatic infections can be transmitted to others. So as long as the test is nucleic acid positive, it must be isolated.
Beijing News reporter Ni Wei Dai Xuan
http://www.bjnews.com.cn/feature/2020/02/10/687510.html
