A number of preliminary studies on the immune escape ability of the Aumequeron strain recently released show that compared with other new coronavirus strains such as Delta, the level of neutralizing antibody protection after receiving 2 doses of the new crown vaccine after receiving the "attack" of the Omiljun strain has decreased significantly compared with other new coronavirus strains such as Delta.
However, a third booster injection on top of the existing vaccine is expected to retain a better neutralization activity against the Omikejong variant. In the face of the Opmi Kerong variant, 3 doses of the new crown vaccine has become the choice for more and more countries.
Outside of South Africa, the UK is also reporting an increasing number of cases of Omiljung. The UK government has announced on 12 December that it will launch intensive vaccinations for people over the age of 18.
In China, on December 13, the official website of Zhifei Bio released the news that the recombinant new crown vaccine that is a 3-dose immunization program can still provide good protection against the Aomi Kerong variant strain. The study organized by the Institute of Microbiology of the Chinese Academy of Sciences found that 78% of the subjects' serums tested positive for neutralizing antibodies to the Semikron variant, of which the serum of the subjects with a gap of more than 4 months between the second and third doses of immunity, 100% of the neutralizing antibodies of the Semikron mutant strains were positive, and the mean titer of the neutralizing antibody was only about 3 times lower than that of the prototype strain.
Zhifei Bio said, "This is better data than other marketed vaccines that have been reported so far." ”
Citizens wearing masks walk through the streets of London, England, on December 9. The British Health Security Agency said on the 10th that the mutated new coronavirus Olmiquerong strain is more contagious than the Delta strain. If this continues at its current rate, by mid-December, the Omiljung strain will account for more than 50% of new cases in the UK, becoming the main strain spreading in the country. Xinhua News Agency/AFP
There are 3 important issues to focus on regarding Omikeron
On November 26, the World Health Organization (WHO) announced that the new coronavirus mutant strain, Omilon, was listed as a "mutant strain of concern" (VOC). As of 12 December, the Omiljung strain had spread to 63 countries and territories, and the variant spread rapidly in South Africa and the United Kingdom.
Daniel Zhang, a researcher at the Institute of Viral Disease Prevention and Control of the Chinese Center for Disease Control and Prevention, believes that for the Aomi Kerong variant, three issues need to be paid attention to: First, we must pay attention to the changes in the transmissibility and pathogenicity of the Omicron variant. At present, there are no systematic epidemiological, virological and clinical medical data on the transmissibility and pathogenicity of Omicron variants;
Second, we should pay attention to the Increased Risk of Re-infection of the Omicron variant. Preliminary evidence suggests that the Omicron strain has an increased risk of re-infection compared to the other 4 VOCs. In almost all provinces of South Africa, the number of cases of infection with the Omicron variant is increasing;
Third, we should pay attention to the effects of immune escape of the Omicron variant strain. The Omicron strain also has a triple mutation of "K417N+E484A+N501Y", suggesting that the strain has the potential to increase the ability of immune escape. The ability of the Omicron variant to immunize to escape from existing vaccines needs to be further studied.
The neutralizing activity of the vaccine against Omikejong is significantly reduced, or a third dose may be required
At present, a number of laboratory serological studies on the Omiljung strain of the new coronavirus vaccine have been pre-published, mainly targeting the mRNA vaccine developed by Pfizer and BioNTech.
On December 7, a research team led by the University of KwaZulu and Natal in South Africa released the world's first Omiljung serum neutralization trial data, in which researchers isolated the Omiljung mutation strain from a positive swab sample of the new crown virus in South Africa, and used the D614G-carrying mutation strain as a control group, and drew 14 plasma plasma from volunteers who had received the Pfizer/BNT162b2mRNA vaccine for in vitro neutralization tests.
According to previous nucleic acid and antibody test results, 6 of the 14 plasma doses came from people who recovered from COVID-19 infection. That is to say, these 6 plasma parts have dual antibodies induced by natural infection and vaccination, and the other 8 parts only have vaccine-induced antibodies.
As a result, all the plasma tested showed excellent neutralization activity on the D614G strain, while for the Omikejong strain, the neutralization effect was weakened.
The D614G mutant strain is a mutant strain that has been monitored as early as February 2020 and belongs to the mutant strain that was endemic and concerned in the early stages of the epidemic. In June 2020, the strain that triggered the outbreak in Xinfadi, Beijing, was a mutant strain carrying D614G.
From the data point of view, the difference in neutrality titer of the plasma of the subjects to the two viruses was as high as 41.4 times. That is, the neutralization activity of Omilon decreased by an overall 41.4-fold decrease compared to the D614G mutant strain.
The difference between the neutralization titers of the plasma of the two viruses was as high as 41.4 times, and the neutralization titer of the Omilon strain had just reached the absolute validity threshold preset by the study. Image source: Researcher
"Although the study only targeted antibody immunity and did not take into account cases such as cellular immunity, it can be seen that the vaccine's protection against infection of the Aumechjong strain has decreased." It is believed that vaccines still have some ability to prevent severe illness and death. Peter van Heusden, a bioinformatician at South Africa's National Institute of Bioinformatics, said at a media sharing session.
On December 8, Pfizer and BioNTech announced that the serum neutralization activity of the Pfizer COVID-19 vaccine BNT162b2 vaccinators against the Omiljung mutant strain decreased; however, after the third dose, the neutralizing activity of serum antibodies increased by 25-fold. The company expects to develop a vaccine against Opichron in March 2022 if circumstances warrant.
On December 11, an Israeli study came to a similar conclusion. The study, conducted by the Sabah Medical Centre in Israel and the Central Virology Laboratory of the Ministry of Health, compared the serum of 20 people who had received 2 doses of the BNT vaccine 5-6 months earlier with the serum of another 20 people who had received the third dose of the vaccine a month earlier for the Omiljung strain. Studies also found that the neutralization activity against Omexon decreased after 5-6 months of 2 doses of the vaccine, but still had higher activity if the third dose was given.
On 11 December, the UK Health Security Agency, a new uk government agency, also released an updated study that has not yet been peer-reviewed. Studies have shown that the vaccine ChAdOx1-S and BNT162b2 vaccines developed by AstraZeneca and oxford universities have been significantly less effective in preventing the onset of symptomatic disease caused by the Omicron strain after a long period of full immunization (2 injections) compared with the Delta strain. However, if the third intensive injection is continued, the effectiveness of the vaccine to prevent infection can be restored to 70-75%.
As of 12 December 2021, a cumulative total of 3137 cases of Infection in Aumecreon have been reported in the UK. On December 12, British Prime Minister Boris Johnson announced in a televised speech that the UK has raised the alert level of the new crown epidemic to the highest level of 4 due to the surge in the number of infections in Omi kerong. At the same time, the UK has also expanded the coverage of enhanced needle vaccination to over 18 years old.
Recombinant COVID-19 vaccine produced by Zhifei Biotech.
Progress in Chinese research on Aomi Kerong
There are also some research trends in China on the immune escape ability of Omi kerong.
Recently, the journal Emerging Microbes & Infections published online the latest study by the Team of Wang Youchun/Huang Weijin of the China Institute of Food and Drug Control ("The significant immune escape of pseudotyped SARS-CoV-2 Variant Omicron"). Using pseudoviral techniques, the team designed and constructed the new coronavirus variant Omicron pseudovirus, tested serum samples from 28 convalescent patients with neutralizing antibodies, and compared them with other VOC (Alpha, Beta, Gamma, Delta) and VOI (Lambda, Mu) strains.
The results showed that the mean neutralizing activity of these convalescent serums on Omicron was reduced to 66, which was 8.4 times lower than that of the D614G reference strain (ED50=556), while the neutralizing activity of these convalescent serums against other VOC and VOI pseudoviruses was only reduced by about 1.2-4.5 times.
"The results of this in vitro pseudovirus study show that the Omicron variant has significantly escaped immune protection caused by previous infections of the new coronavirus, and the escape effect is far superior to that of other VOC and VOI variants."
Can the immunity induced by the domestic vaccine resist the Aomi Kerong infection?
For the Aomi Kerong strain, Kexing Holding Biotechnology Co., Ltd., with the assistance of relevant ministries and commissions of the state and the relevant departments of the Hong Kong Special Administrative Region, obtained a nasopharyngeal swab sample of the new coronavirus Omicron variant strain on December 5, and cooperated with Professor Qin Chuan's team of the Institute of Medical Laboratory Animals of the Chinese Academy of Medical Sciences to carry out virus isolation and whole gene sequencing, and has successfully isolated the Omicron variant and obtained the sequencing results.
Kexing and the team of academician Yuan Guoyong of the University of Hong Kong have signed a cooperation agreement to introduce samples of the Omicron mutant strain isolated by HKU, which arrived in Beijing on the afternoon of December 9 and transferred to the P3 Laboratory of the Institute of Medical Laboratory Animals of the Chinese Academy of Medical Sciences for research.
Kexing said that after obtaining the new coronavirus Semikron variant, Kexing can better guarantee the research of vaccine crossover testing and vaccine poison screening, so as to understand the impact of the Semikron variant on the existing new crown vaccine, and then evaluate the necessity of developing the new coronavirus Semikron variant vaccine.
Zhang Yuntao, chief scientist and vice president of Sinopharm China Biologics, said in Shanghai on December 9 that China Biologics has made systematic layout and technical reserves for the research and development of the newly discovered Aomi Kerong strain and the development of vaccines, and will carry out research in the near future.
Zhang Yuntao said that Sinopharm China Biologics has developed 4 new coronavirus vaccines on 3 technical routes (inactivated vaccines, recombinant protein vaccines and mRNA vaccines), and China Biologics has laid out research and development work for the Omikerong variant on the existing 3 technical routes.
On December 13, the official website of Zhifeilong Kema Bio released the news that the recombinant new crown vaccine can still provide good protection against the Aomi Kerong variant.
This study was organized by the Institute of Microbiology of the Chinese Academy of Sciences, and the serum of subjects 1 month after the full immunization of 3 recombinant NEW CORONAVIRUS vaccines was detected by the pseudoviral cross-neutralization test method. The results showed that 78% (25/32) of the subjects' serums tested positive for neutralizing antibodies to the Omikejong variant, among which the serum of the subjects with a gap of more than 4 months between the second and third doses of immunity tested positive for neutralizing antibodies in the Omikejong variant, and the average titer of the neutralizing antibody decreased by about 3 times compared with the prototype strain.
At the same time, only 6.25% (1/16) of the serum of those who recovered from COVID-19 as a control group tested positive for neutralizing antibodies of the Omikejong mutant strain.
Written by: Nandu reporter Wu Bin from Beijing