Li Wenliang is also a victim of false negative? Various hypotheses still need to be tested one by one

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 Li Wenliang is also a victim of false negative? Various hypotheses still need to be tested one by one


Dr. Li Wenliang, the anti epidemic hero, had a very short interval between his sudden deterioration and his death. However, according to Li Wenliangs information in an interview on January 30, his nucleic acid test on that day had turned negative, and turned positive two days later. This also caused the netizens discussion: the nucleic acid test has turned negative, how can the condition worsen? Is Li Wenliang also the victim of false negative

There are also online rumors that the new coronavirus is too smart and will be invisible and Yin and Yang change indefinitely, so it is likely to turn Yin and Yang again.

The national health and Health Commission and the World Health Organization held a press conference on February 7 respectively, without disclosing Li Wenliangs disease history and treatment process. Until Li Wenliangs disease history was published, none of these guesses had scientific basis.

The mechanism of how the virus causes severe disease is not very clear, and various hypotheses need to be tested one by one, a former viroimmunologist at the Pasteur Institute of Chinese Academy of Sciences told first financial reporter

The false proposition of Yin to Yang in nucleic acid detection

Its a false proposition to turn positive after turning negative, because the detection of turning negative cant be the only basis for judging whether the patient is still infected with the virus. The virus load is low and may not be detected. A professional in the diagnosis industry told the first financial reporter.

Wang Chen, an expert in critical care medicine and President of the Chinese Academy of Medical Sciences, said in an interview with CCTV on February 5: not all patients can detect nucleic acid positive, but only 30% to 50% of the patients who are really infected with the new type of coronavirus are positive. There are still a lot of false negatives through the method of collecting throat swabs of suspected cases. In other words, more than half of human nucleic acid tests that actually infect the new coronavirus will be negative..

A clinician in the infection department of Shanghai Huashan Hospital told the first financial reporter: there are many factors that cause false negativity, probably two factors. One is the sampling of clinicians. Now most of them rely on nasopharyngeal swabs for sampling. It is difficult to detect nucleic acid, and it requires experienced doctors to collect high-quality samples. The other key factor is the flexibility of the kit Sensitivity.

In response to the lack of sensitivity of reagents, the above diagnostic industry told the first financial reporter that at the beginning of the outbreak of the virus, the use of nucleic acid detection is also a stopgap. Nucleic acid detection is not the gold standard for virus detection. But when the new virus appears, the method of nucleic acid detection is the fastest and most effective.

Nucleic acid detection belongs to molecular diagnosis, which is the fastest and relatively easy to do, but its disadvantages are also obvious in this diagnosis, that is, its sensitivity is low, so it is often used in scientific research laboratories in the past, and less used in clinical practice. The above diagnosis industry told the first financial reporter.

He said that in clinical medicine, the immunological diagnosis method of combined detection of antibody and antigen is the gold standard, which can detect whether there is a new virus in the patients body. If there is no new virus in the body, then no antigen will be produced. But the detection technology of antigen is very difficult, and it cant replace the detection of nucleic acid reagent at present. The insider told the first financial reporter. However, with the increase of the number of cases, more data samples are provided for the development of antibody reagents.

Discharge standard should be improved

This virus is really unusual. A person from China CDC told the first financial reporter.

In view of the limitations of the existing technical means, such as the sensitivity of reagents cannot be improved in a short period of time, clinicians believe that the clinical observation and testing of patients who can be judged to be discharged after a period of treatment cannot be relaxed, and the observation time should be extended for patients who have been discharged.

In the diagnosis and treatment plan for pneumonia with new coronavirus infection (trial version 5) published by the national health and Health Commission on February 5, the suggestions for the release of isolation and discharge standard are: the temperature returns to normal for more than 3 days, the respiratory symptoms improve significantly, the pulmonary imaging shows that the inflammation is obviously absorbed, and the detection of respiratory pathogenic nucleic acid is negative for two consecutive times (the sampling interval is at least 1 day), which can Discharge from isolation or transfer to the corresponding department for treatment of other diseases according to the condition.

Negative nucleic acid test is not the only criterion for discharge, but also the clinical manifestations of patients. The above Huashan Hospital Infection doctor told the first financial reporter. Another person who has been engaged in medical diagnosis and testing for a long time told the first financial reporter that before leaving the hospital, two different testing methods should be used to confirm whether it is cured. Besides nucleic acid testing, gene testing can also be carried out. However, he believes that the long cycle of gene testing is a limitation.

Due to the complexity of virus detection, nucleic acid reagent detection can not fully prove the disappearance of the virus. A clinician suggested to the first financial reporter: the second nucleic acid negative is proposed as one of the discharge standards in the current diagnosis and treatment plan, but it can not completely rely on the same kit for repeated detection, and it is still necessary to extend the time of isolation observation.

There is no evidence of virus mutation and no case of secondary infection

In addition, there are some bolder guesses on the Internet that whether the virus has mutated? Whether there is a possibility of second infection in the cured people? In this regard, the national health and Health Commission has repeatedly responded: no virus mutation has been found.

Qiu Haibo, a member of the expert group of the national health and Health Commission, said on February 2: there are no cases of secondary infection at present. Now there are surveillance on patients infected with the new coronavirus. These patients can produce antibodies after two or three weeks of infection, especially those who are cured. Generally, the antibody will last for half a year or more, so the possibility of reinfection within half a year is very small, unless the virus mutates again, but there is no evidence yet.

(function() {(window. Slotbydup = window. Slotbydup| []). Push ({ID: u5811557, container: ssp_, async: true});)) (); Qiu Haibos response has two information quantities: one is that the cured patients can produce antibodies, which is not easy to infect within half a year; the other is that if the virus mutates, the cured patients also have the possibility of infection, but no similar cases have been found. Qiu Haibo said that the virus has no evidence of mutation and has been verified by scientific research. According to a paper published in the national science review by the Pasteur Institute of Chinese Academy of Sciences on January 29, according to the analysis results of the new coronavirus currently published and the genome comparison results uploaded in the public database, the comprehensive analysis shows that the early evolution data of the new coronavirus does not show obvious mutations, especially the virus relationship The key points, however, call for close monitoring of the evolution of the virus in the middle and later stages. Extended reading: about 80 doctors and patients with pneumonia in the hospital of Wuhan mental health center were confirmed to have pneumonia in Zhuhai, a family of six and five passengers were confirmed to have pneumonia in the upper row of the bus. Real time update of the map of new pneumonia. Source: the first financial editor: Wang Ning, nb12468

Qiu Haibos response has two information volumes, one is that the cured patients can produce antibodies, which is not easy to infect within half a year; the other is that if the virus mutates, the cured patients also have the possibility of infection, but no similar cases have been found.

Qiu Haibo said that the virus has no evidence of mutation and has been verified by scientific research. According to a paper published in the national science review by the Pasteur Institute of Chinese Academy of Sciences on January 29, according to the analysis results of the new coronavirus currently published and the genome comparison results uploaded in the public database, the comprehensive analysis shows that the early evolution data of the new coronavirus does not show obvious mutations, especially the virus relationship The key points, however, call for close monitoring of the evolution of the virus in the middle and later stages.