State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR 999078, China.
Int J Biol Sci. 2022 Jul 11;18(12):4629-4641. doi: 10.7150/ijbs.73583. eCollection 2022.
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has undergone multiple mutations since its emergence, and its latest variant, Omicron (B.1.1.529), is the most contagious variant of concern (VOC) which poses a major and imminent threat to public health. Since firstly reported by World Health Organization (WHO) in November 2021, Omicron variant has been spreading rapidly and has become the dominant variant in many countries worldwide. Omicron is the most mutated variant so far, containing 60 mutations in its genome, including 37 mutations in the S-protein. Since all current COVID-19 vaccines in use were developed based on ancestral SARS-CoV-2 strains, whether they are protective against Omicron is a critical question which has been the center of study currently. In this article, we systemically reviewed the studies regarding the effectiveness of 2- or 3-dose vaccines delivered in either homologous or heterologous manner. The humoral and cellular immune responses elicited by various vaccine regimens to protect against Omicron variant are discussed. Current understanding of the molecular basis underlying immune escape of Omicron was also analyzed. These studies indicate that two doses of vaccination are insufficient to elicit neutralizing antibody responses against Omicron variant. Nevertheless, Omicron-specific humoral immune responses can be enhanced by booster dose of almost all type vaccines in certain degree, and heterologous vaccination strategy may represent a better choice than homogenous regimens. Intriguingly, results of studies indicate that all current vaccines are still able to elicit robust T cell response against Omicron. Future focus should be the development of Omicron variant vaccine, which may induce potent humoral as well as cellular immune responses simultaneously against all known variants of the SARS-CoV-2 virus.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）自出现以来经历了多次突变，其最新变体奥密克戎（B.1.1.529）是最具传染性的关注变体（VOC），对公众健康构成重大且迫在眉睫的威胁。自 2021 年 11 月世界卫生组织（WHO）首次报告以来，奥密克戎变体迅速传播，已成为全球许多国家的主要优势变体。奥密克戎是迄今为止突变最多的变体，其基因组中包含 60 个突变，其中 S 蛋白中有 37 个突变。由于目前使用的所有 COVID-19 疫苗都是基于原始 SARS-CoV-2 株开发的，因此它们是否对奥密克戎具有保护作用是一个关键问题，这也是目前研究的重点。在本文中，我们系统地回顾了关于以同源或异源方式接种 2 剂或 3 剂疫苗的有效性的研究。讨论了各种疫苗方案引发的体液和细胞免疫反应，以预防奥密克戎变体。还分析了目前对奥密克戎免疫逃逸分子基础的理解。这些研究表明，接种两剂疫苗不足以引发针对奥密克戎变体的中和抗体反应。然而，在一定程度上，几乎所有类型疫苗的加强剂量都可以增强针对奥密克戎的体液免疫反应，异源接种策略可能比同源方案更好。有趣的是，研究结果表明，所有当前的疫苗仍然能够引发针对奥密克戎的强大 T 细胞反应。未来的重点应放在开发针对奥密克戎变体的疫苗上，该疫苗可能会同时针对 SARS-CoV-2 病毒的所有已知变体诱导强大的体液和细胞免疫反应。
