Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, 518112, Guangdong Province, China.
The Second Affiliated Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, 518112, Guangdong Province, China.
Nat Commun. 2022 Nov 19;13(1):7120. doi: 10.1038/s41467-022-34400-8.
With declining SARS-CoV-2-specific antibody titers and increasing numbers of spike mutations, the ongoing emergence of Omicron subvariants causes serious challenges to current vaccination strategies. BA.2 breakthrough infections have occurred in people who have received the wild-type vaccines, including mRNA, inactivated, or recombinant protein vaccines. Here, we evaluate the antibody evasion of recently emerged subvariants BA.4/5 and BA.2.75 in two inactivated vaccine-immunized cohorts with BA.2 breakthrough infections. Compared with the neutralizing antibody titers against BA.2, marked reductions are observed against BA.2.75 in both 2-dose and 3-dose vaccine groups. In addition, although BA.2 breakthrough infections induce a certain cross-neutralization capacity against later Omicron subvariants, the original antigenic sin phenomenon largely limits the improvement of variant-specific antibody response. These findings suggest that BA.2 breakthrough infections seem unable to provide sufficient antibody protection against later subvariants such as BA.2.75 in the current immunization background with wild-type vaccines.
随着 SARS-CoV-2 特异性抗体滴度的下降和刺突突变数量的增加，奥密克戎亚变体的持续出现对当前的疫苗接种策略构成了严重挑战。在接种了野生型疫苗（包括 mRNA、灭活或重组蛋白疫苗）的人群中，已经发生了 BA.2 的突破感染。在这里，我们评估了最近出现的亚变体 BA.4/5 和 BA.2.75 在两例接种过灭活疫苗并发生 BA.2 突破感染的人群中的抗体逃逸情况。与针对 BA.2 的中和抗体滴度相比，在 2 剂和 3 剂疫苗组中，针对 BA.2.75 的中和抗体滴度均显著降低。此外，尽管 BA.2 突破感染诱导了对后来的奥密克戎亚变体的一定交叉中和能力，但原始抗原性现象在很大程度上限制了对变异特异性抗体反应的改善。这些发现表明，在当前使用野生型疫苗的免疫背景下，BA.2 突破感染似乎无法为后来的亚变体（如 BA.2.75）提供足够的抗体保护。
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