On May 10, according to the WeChat account of Huashan Infection, the National Center for Infectious Disease Medicine, the Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, the team of Professor Zhang Wenhong of Huashan Infection and the team of Professor Wang Pengfei of the School of Life Sciences of Fudan University jointly evaluated the immune escape characteristics of four subtypes of the Omicron variant after two doses of inactivated vaccine and the third dose of enhanced vaccination, and the relevant results were published in Cell Host and Microbe magazine on May 8 (2021 IF 21.023).
The study further confirms that for people who are suitable for vaccination, the promotion of vaccine-boosted injections is still one of the effective means to prevent the spread of SARS-CoV-2, especially the transmission of the Omiljung strain.
As of May 2022, more than 510 million cases of COVID-100 have been reported worldwide. The Omiljung variant of SARS-CoV-2 was first detected in November 2020, and has been widely circulated around the world, with multiple sub-lineages, named BA.1, BA.1.1, BA.2, BA.3, BA.4, BA.5, etc., and recombinant subtype XD, XE, XF strains have also been recently detected. In the past 1-2 months, the proportion of BA.2 subtypes has risen rapidly, becoming the main epidemic strain in many recent outbreaks. Epidemiological studies have shown that BA.2 has been detected in more than 40 countries and regions, its transmission capacity is about 30% higher than BA.1, and the viral load after infection is 2 times higher than that of BA.1; its subtype BA.2.12.1 contains L452Q mutations, which is more detected in the United States and has a transmission advantage.
The study found that the antibody titer levels of the Two-Shot Inactivated Vaccine subjects to the Semickon strain were at least 5.3 times lower than those of the original strain. Experimental evaluations of four subtypes of pseudoviruses showed that the neutralizing antibody titers against BA.2 were similar to or lower than BA.1. After the third dose of homologous (inactivated vaccine) or heterologous inoculation, the antibody titer is significantly elevated, and the antibody positivity rate reaches at least 75%. Recently, three recombinant lineages (XD, XE, and XF) have been reported, but their antibody escape is not expected to differ significantly from the 4 Semiconian sublineages studied because their S proteins are identical to BA.1 or BA.2.
【Reference】
1. 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.（荆雪涛）
