Recently, the national infectious diseases Medical Center, Shanghai Key Laboratory of infectious diseases and biosafety emergency response, Professor Zhang Wenhong's team of Huashan infection and Professor Wang Pengfei's team of School of life sciences of Fudan University jointly evaluated the immune escape characteristics of four subtypes of Omicron mutant after two doses of inactivated vaccine and the third dose of booster vaccination. The relevant results were published in the journal Cell Host and microbe (2021 if 21.023) on May 8. By may 2022, more than 510million cases of novel coronavirus pneumonia had been reported worldwide. The Omicron variant of sars-cov-2 was first detected in November 2020. At present, it has been prevalent all over the world, and there are many sub lineages, named ba 1，BA. 1.1，BA. 2，BA. 3，BA. 4，BA. 5 et al. In addition, recombinant subtypes XD, Xe and XF strains have also been detected recently. In the past 1-2 months, BA The proportion of subtype 2 increased rapidly and became the main epidemic strain in many places recently. Epidemiological studies show that ba 2 has been detected in more than 40 countries and regions, and its transmission capacity is lower than ba 1 is about 30% higher than that of Ba 1 high 2 times; Its subtype ba 2.12.1 it contains l452q mutation, which is more detected in the United States and has the advantage of transmission. Sensitivity of Omicron subtypes to neutralization induced by existing vaccines or mediated by monoclonal antibodies The study found that the antibody titer of subjects vaccinated with two doses of inactivated vaccine against Omicron strain decreased by at least 5.3 times compared with the original strain. Experimental evaluation of four subtypes of pseudovirus showed that for BA Neutralizing antibody titer of 2 and ba 1 similar or lower than ba 1。 After the third dose of homologous (inactivated vaccine) or heterologous vaccination, the antibody titer increased significantly, and the antibody positive rate reached at least 75%. Recently, three recombinant lineages (XD, Xe and XF) have been reported, but their antibody escape is not expected to be significantly different from the four Omicron sublines studied because their s protein is different from Ba Or ba.1 2 same. Omicron ba Previous exploration on neutralization ability of 1 strain In fact, in December of 21, Professor Zhang Wenhong's team and Professor Wang Pengfei's team of Huashan infection evaluated Omicron BA in two inactivated vaccines and three homologous / heterologous vaccination serum samples The study found that the antibody titer of the two inactivated vaccines against the Omicron variant decreased significantly, and the neutralizing antibody titer decreased to 6.04, about 10 times lower than the original strain. No matter what type of third dose enhancement (inactivated vaccine or recombinant subunit protein vaccine), the positive rate of neutralizing antibody titer of serum samples to Omicron strain reached 100%. Scientific significance of this study This study further confirmed that for people suitable for vaccination, promoting vaccine and strengthening needle injection is still one of the effective means to prevent the spread of sars-cov-2, especially to deal with the spread of Omicron strain. Although the mortality and severe rate of Omicron strain are lower than those of the original strain and delta strain, it can still lead to an increase in the severe rate of the elderly or immunodeficient population. Therefore, for the population suitable for vaccination, it is important to further improve the proportion of whole course vaccination and strengthen vaccination. [References] one https://outbreak.info/ 2. Ai, Jingwen et al.Antibody Evasion of SARS-CoV-2 Omicron BA. 1, BA. 1.1, BA. 2 and BA. 3 Sub-lineages. Cell Host Microbe,DOI: https://doi.org/10.1016/j.chom.2022.05.001 3.Ai Jingwen,Zhang Haocheng,Zhang Yi et al. Omicron variant showed lower neutralizing sensitivity than other SARS-CoV-2 variants to immune sera elicited by vaccines after boost. [J] . Emerg Microbes Infect, 2022, 11: 337-343. 4.Wang Xun,Zhao Xiaoyu,Song Jieyu et al. Homologous or heterologous booster of inactivated vaccine reduces SARS-CoV-2 Omicron variant escape from neutralizing antibodies. [J] . Emerg Microbes Infect, 2022, 11: 477-481. (Xinhua News Agency)