Expert explanation: does the novel coronavirus vaccine “strengthen the needle” play? Who called? What injection?

The transmission chain of COVID-19 delta mutant strain is still spreading from Nanjing Lukou International Airport

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From the end of May this year to Guangdong, to Nanjing today, China has suffered the second COVID-19 mutant strain

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In both encounters, confirmed patients who had been vaccinated with two doses of novel coronavirus inactivated vaccine were found

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Most people in China are vaccinated with inactivated new coronal vaccine with two vaccination procedures

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Two injections of inactivated novel coronavirus vaccine, which is also the immunization procedure clearly recommended in the first version of the technical guide for novel coronavirus vaccination issued by the National Health Commission

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Photo source: Vision China on July 29, many experts proposed in an interview that some key populations should be vaccinated with the third dose of vaccine to enhance immunity

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At present, there are many factors to be considered in the third injection of the novel coronavirus vaccine

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Experts answered in detail why the third injection should be given, who should be given it, and whether it is possible to develop the third injection vaccine against the delta variant strain

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Why do you propose to strengthen the third needle? Neutralizing antibody level is an important index to evaluate the protective efficacy of novel coronavirus vaccine

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At present, many studies have shown that the level of neutralizing antibody in human body will decrease significantly after 6 months of novel coronavirus vaccine“ This situation is not ideal and is not conducive to epidemic prevention and control

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” Jin Dongyan, a professor and virologist at the school of biomedicine of the University of Hong Kong, said that the inactivated vaccine has a poor ability to activate cellular immunity, but it can activate memory B cells, that is, remember the virus and react when it is infected next time, which is useful to reduce the severity of the disease, But reducing infection is not ideal for an important goal“ If the vaccine is given, there will still be cluster infection, which will spread from one to another

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This situation is certainly unfavorable to prevention and control

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” Jin Dongyan believes that this also affects people’s confidence in the vaccine

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Jin Dongyan believes that at present, the novel coronavirus vaccine has been implemented for some people in foreign countries, and this problem should also be considered in China

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According to the news released by the British Ministry of health on June 30, the Joint Committee on vaccination and immunization of the independent expert group of the government suggested that the third dose of booster injection should be given to the most vulnerable people in the epidemic in September, so as to strengthen the protection of these people before this winter

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However, the British Ministry of health also said that with the continuous data analysis, the committee’s final recommendations may change

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At present, the UK is evaluating the effect of the booster injection of the novel coronavirus vaccine through clinical trials

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It is expected that the research team will announce the preliminary results of this clinical trial in September this year

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What are the main considerations for strengthening immunization? What are the main factors to consider for the third injection of the novel coronavirus vaccine? On July 29, Lu Xuexin, an expert from the Institute of viral disease prevention and control of China CDC, said in an interview with surging news that the first is safety, the second is effectiveness, and then the accessibility of vaccines

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It is worth mentioning that China’s research on the safety and effectiveness of the third dose of Xinguan vaccine has also been published, which provides data support for the next vaccination strategy

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Recently, Kexing published a phase II clinical trial of a novel coronavirus inactivated vaccine on medrxiv, a preprint platform of health science

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The interim results showed that although the neutralizing antibody level decreased after 6 months, the immunization procedure of the two doses of vaccine produced a good immune memory

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After the third dose, it could quickly induce a strong immune response, and the neutralizing antibody titer increased significantly, The neutralizing antibody titer 28 days after the third dose was 3-5 times higher than that 28 days after the second dose, and the longer the interval between the third dose and the second dose, the higher the growth multiple

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In the discussion part, the author said that although the third dose of vaccination may be essential, the formulation and implementation of the strengthening plan should comprehensively consider the local epidemic situation, infection risk, vaccine supply and other relevant factors

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According to the current situation, in the short and medium term, ensuring that more people complete two doses of inactivated vaccine should be a higher priority than booster vaccination

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Lu Xuexin believes that the data released by Kexing also show that the safety and neutralizing antibody titer of the third injection of vaccination are good, which is also a candidate scheme for epidemic prevention and control under the current state of emergency

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Whether to fight or not needs to wait for the policies of relevant departments

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Who gave the third shot? If the protection period of 6 months is taken as the limit, some people have been vaccinated with the second dose of novel coronavirus inactivated vaccine for 6 months

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So, does everyone have to get a third shot? What are the considerations“ If the third needle is really implemented, according to the urgency and risk assessment, front-line personnel, entry-exit related personnel, employees in high-risk industries and public service personnel should belong to the first echelon

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” Lu Xuexin said

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Jin Dongyan also believes that some high-risk groups, such as medical staff, airport staff and elderly caregivers, need to be vaccinated with the third injection as soon as possible

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First, improve the level of neutralizing antibody, which is good but not bad

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Whether the person vaccinated with the third injection needs to test the antibody level before deciding whether to vaccinate“ The novel coronavirus antibody test should become a routine operation and is reasonable

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” Jin Dongyan believes that it is a pity that antibody detection has not been of great use at present

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What vaccine should the third injection be given? Concerns about the protective effect of the novel coronavirus vaccine also stem from the mutation of COVID-19

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The fact that the rate of vaccine protection has been reduced by the delta virus has become a fact that must be faced

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According to Israel’s Ynet News Network reported on July 5, the latest data from the Israeli Ministry of health showed that from June 6 to early July, more people who had been vaccinated with Pfizer vaccine were infected with the virus

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The anti infection efficiency of Pfizer vaccine has decreased from 94.3% before June this year to 64% today, but the vaccinated infected people only have mild symptoms

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The data published by Kexing show that the third dose of its novel coronavirus inactivated vaccine significantly improves the immune response, and the neutralizing antibody titer is several times higher than that after two doses, but whether the mutant has the same effect remains to be studied

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In view of the global spread of the COVID-19 delta mutant strain, whether the third pin inactivated novel coronavirus vaccine can be added to the inactivated dedelta strain, the experts responded to the news during the rush

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The third vaccine plus the inactivated delta strain seems very simple

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It’s still very difficult to make this new vaccine

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” Lu Xuexin told surging news that because this involves many aspects such as the management regulations, safety and effectiveness of biological drugs, this process involves many links such as virus strain culture and screening, vaccine production technology, clinical trials and regulatory approval

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It also needs to consider the influencing factors such as the rate of virus variation and the timeliness of vaccination“ The replacement of the virus strain is slow but not urgent, so it can’t be done

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” Jin Dongyan also said that the virus strain should be updated in the long run, but there is no unified international decision on whether to replace the virus strain

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Jin Dongyan believes that now the virus is racing against human immunity

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Before, alpha strain was still popular, but now it has become delta strain

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Maybe other strains will be popular again when a new vaccine is made“ What we need to consider now is to give the third shot

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We can just give the existing vaccine

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” Jin Dongyan said that studies have shown that “mixed beating” can better stimulate human immune response

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If conditions permit, vaccines with different technical routes can be selected for the third injection

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For example, those previously inactivated can be given recombinant neocrown vaccine or fubitai (mRNA vaccine)

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Actively vaccinate yourself, others and your family!.

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