After vaccinating novel coronavirus vaccine, why does antibody test have yang to have yin?

The author Hou Bingbing, Qi Wenfeng and Li Xiaole said that with the development of the new coronavirus vaccination work, the recipients are more concerned about whether the body can produce immunity to the new coronavirus after vaccination

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Therefore, there are some people who go to medical institutions for antibody detection of new coronavirus after vaccination for a period of time

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These people antibody test results show that there are positive and negative, why such a result? We summarize and analyze this as follows

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Is there an immune response in the body? Not all people will have immune response after the new coronavirus vaccine is inoculated into the human body

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Take the inactivated new coronavirus vaccine as an example, although the neutralizing antibody conversion rate is as high as 99.52% [1], not 100% of the recipients can have a complete immune response after the new coronavirus vaccine is inoculated, which may be related to the different recognition and response ability of each person’s immune system

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Second, the antibodies produced by different vaccines are different, and the antibodies produced by different types of new coronavirus vaccines are also different

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For example, the recombinant vaccine of new coronavirus (adenovirus vector) only carries the gene of S protein of new coronavirus [1]

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If the corresponding immune response is produced after inoculation, it can only produce antibodies related to S protein of new coronavirus, but can not produce other antibodies related to new coronavirus except s protein

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If the antibody detection reagent of new coronavirus is not the antibody against S protein of new coronavirus, the antibody detection may be negative after inoculating recombinant vaccine of new coronavirus (adenovirus vector)

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Is the antigen coated in the triple antibody test reagent the same as the vaccine? The antigens coated in antibody detection reagents from different manufacturers are also different, such as s, n or S + N protein antigens [2]

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If the antibody produced by the new coronavirus vaccine in human body is not consistent with the antigen coated in the reagent, then the final test results may be different

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(4) after vaccination, IgM antibody first appeared in human body (about 5-7 days), and IgG antibody appeared later (about 10-15 days) after human infection with pathogens [3]

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IgM antibody in the body for a short time, disappear quickly, in the blood for several days to several weeks, the content increased, indicating recent infection; IgG antibody in the blood for a long time (months or years or even decades), IgG antibody content increased, indicating previous infection with related pathogens

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If the test is carried out before antibody generation after vaccination, the test results may be negative for IgM / IgG; if the test is carried out after vaccination for a long time, the test results may be negative for IgM and positive for IgG

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The sensitivity, specificity and anti-interference ability of different detection reagents are also different

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If the patient has other diseases (rheumatoid, SLE and other autoimmune diseases), antigen cross reaction, heterophilic antibody, rheumatoid factor, drugs, sample collection, transportation, reagents, instruments and other abnormal factors in the detection process will also affect the detection results

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Conclusion after the vaccination of the new coronavirus vaccine, we are very concerned about whether our body produces antibodies, so the vaccine recipients go to the medical institutions to detect the antibodies of the new coronavirus

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However, the antibodies detected by medical institutions are not used to verify the immune effect of the new coronavirus vaccine

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The negative or positive test results can not indicate whether there are protective antibodies against the new coronavirus in the body

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In order to determine whether the body produces protective antibodies against the new coronavirus, neutralizing antibody related detection is needed to determine [4]

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[References] [1] Zhu Yao, Wei Yi Na, Sun Chang, et al

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Research progress on New Coronavirus pneumonia vaccine [J]

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preventive medicine

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http://kns.cnki.net/kcms/detail/33.1400.R.20210115.1345.002.html [2] Li Hui, Li Yongyin, Zhang Zhigao, etc..2019.2019 antibody colloidal gold detection method and clinical performance evaluation [J]

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Chinese Journal of infectious diseases, 2020, 38 (03): 139-144.[3] People’s Republic of China national health and Health Committee

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New Coronavirus pneumonia diagnosis and treatment plan (trial version 7) [S]

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Beijing: People’s Republic of China national health and Health Committee, 2020.[4] Hou Bingbing, Qi Wenfeng, Li Xiaole

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What is the difference between the antibody produced after the novel coronavirus vaccination and the novel coronavirus antibody detected in the hospital? Official account of laboratory medicine

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2021.02.03

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