August 13, 2022

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Current COVID-19 vaccines still effective against mutant strains?

Current COVID-19 vaccines still effective against mutant strains?

 

Current COVID-19 vaccines still effective against mutant strains?  What should I do if the new coronavirus mutation reduces the effectiveness of the vaccine?

 

Current COVID-19 vaccines still effective against mutant strains?

 

The South African variant has an impact on the vaccine’s effectiveness, but the current impact on the inactivated vaccine’s effect is uncertain, and the Brazilian variant is even less known.

Foreign mRNA may consider another strategy to strengthen immunity against mutant viruses. At this time, the advantages of mRNA are reflected. The turnaround is fast. It is said that it can be designed in only 2 weeks. Our own mRNA research and development must also take the variants into consideration . Now, let’s talk about the basic vaccine first.

Israel has the largest proportion of vaccinated people, and the hospitalization of the elderly has improved. The hospitalization rate of people over 60 due to COVID-19 has plummeted by 60%, and this is only three weeks after the first dose of vaccination, which means that there is no After the ideal second dose (usually a month or so in total), the effect has been so significant. But yesterday on the 25th, Israel announced the suspension of all passenger flights. I guess it might be to mutate the virus and set aside time for vaccination.

 

Recently, the United Kingdom, South Africa and Brazil have successively discovered new variants of the new coronavirus. Some people in the health field worry that the current vaccine may not be effective against these new mutant strains, which will increase the possibility that people who have been infected or vaccinated will re-infect COVID-19. Current preliminary research shows that the mutant strains circulating in the United Kingdom cannot escape the vaccine-mediated immune response, but the effect of the existing COVID-19 vaccine on the strains circulating in South Africa and Brazil is not yet fully clear.

Moderna just announced on the 25th that its mRNA-1273 vaccine is still effective against the British mutant B.1.1.7 and the South African mutant B.1.351. This result comes from a collaborative study with NIH VRC. Moderna revealed that this study evaluated the serum neutralization of subjects vaccinated with mRNA-1273 in the phase 1 clinical trial and the serum neutralization of NHP (monkey experimental animals) vaccinated with 30 or 100 ug vaccine. active. The study found that the serum neutralization activity was still significant for the B.1.1.7 strain and did not significantly decrease. The neutralizing activity of mRNA-1273 against B.1.351 decreased by 6 times after vaccination, but the serum after immunization in rhesus monkeys still maintained effective antiviral neutralizing activity. This conclusion is very similar to the conclusions of many previous preprint articles. It seems that the South African strain B.1.351 mutation has a more significant effect on serum neutralization. This is because the South African strain B.1.351 E484K mutation in the RBD has a more obvious effect on the neutralization activity. Moderna is developing a next-generation COVID-19 vaccine against the new mutant strain.

 

 

Chief Expert of CDC: If necessary, the upgrade can be completed in about 2 months

Shao Yiming, chief AIDS expert at the China Centers for Disease Control and Prevention, said in an exclusive interview with a reporter from the Global Times that he is responding to the problem that the mutation of the new coronavirus may reduce the effectiveness of existing vaccines. If it is really necessary to upgrade the vaccine, China’s inactivated vaccine is expected to be completed in about 2 months, and the entire process is not complicated.

 

Inactivated vaccines and mRNA vaccines are the two fastest technical routes to respond to the escape mutation of the new coronavirus, while technical routes such as viral vectors and protein vaccines take much longer. He said that if there is a need to upgrade vaccines to deal with the escape of the virus in the future, Chinese companies only need to replace the seed virus in the virus fermentation tank after receiving the mutant strain. Other processes do not need to make any adjustments. The upgrade update can be completed within a month.

 

He believes that the upgrade of mRNA vaccines will take about a few weeks. Since mRNA is a chemical synthesis technology, inactivated vaccines are biotechnology. The latter takes time to cultivate cells, multiply and inactivate viruses, so there are many quality control factors for inactivated vaccines. , Will be slightly slower than the upgrade process of chemical synthesis and modification of mRNA vaccines, but the time difference between before and after should not exceed 1 month.

Is the existing COVID-19 vaccine effective against mutant strains? Shao Yiming explained that it is normal for vaccines to protect homologous strains well, but poorly to heterologous strains, and that vaccines deal with any pathogen. He told reporters, according to China’s vaccine companies and research laboratories, domestic vaccine-induced antibodies for the first half of last year has not changed in Europe, South America, and the ability to crown a new strain of the United States appear, but nearly emerging Britain, South Africa and The neutralizing ability of the new mutant strains in South Africa has declined to varying degrees. Foreign COVID-19 vaccines, like the situation in some countries, are all developed based on the sequence of the epidemic virus discovered in Wuhan early last year.

 

The Chinese vaccine expert said that the long-term development of the COVID-19 vaccine should consider imitating the model of influenza or HPV vaccines, establishing a global n COVID-19 virus mutation monitoring network, determining the composition of the vaccine strain based on regular monitoring data, and making the COVID-19 vaccine multivalent Vaccine, because it is not certain which strain will become the dominant strain in the area where the vaccinated person is located, nor can it guarantee that the vaccinated person will not be attacked by the inferior strain at all. Multivalent vaccines are helpful to prevent infectious diseases with multiple strains at the same time. .

 

(source:internet, reference only)


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