Chekol Abebe Endeshaw, Tiruneh G/Medhin Markeshaw, Behaile T/Mariam Awgichew, Asmamaw Dejenie Tadesse, Mengie Ayele Teklie, Tadele Admasu Fitalew, Tilahun Muche Zelalem, Asmare Adela Getachew
Department of Medical Biochemistry, College of Health Sciences, Debre Tabor University, Debre Tabor, Ethiopia.
Department of Medical Biochemistry, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
Infect Drug Resist. 2022 Apr 15;15:1871-1887. doi: 10.2147/IDR.S360103. eCollection 2022.
Since the emergence of COVID 19, the authentic SARS-CoV-2 has evolved into a range of novel variants that are of more global concern. In late November 2021, the Omicron (lineage B.1.1.529) variant was identified as a new variant and considered as the fifth variant of concern. Omicron harbors a genetic profile that is exceedingly unusual, with a huge number of mutations. Above thirty mutations are localized in the S protein, while some are found in other structural and non-structural proteins. Half of the mutations in the S protein are in the RBD, which is a major target of antibodies, showing that Omicron mutations may affect antibody binding affinity to the S protein. The Omicron variant has been found to result in immune escape, therapeutic or vaccine escape, as well as increased transmissibility and reinfection risk, explaining its rapid international spread that sparks a global alarm even more serious than the previously reported variants. Omicron has the capability to bypass at least some of the multi-faceted immune responses induced by prior infection or vaccination. It is shown to extensively escape neutralizing antibodies while evading cell mediated immune defense to a lesser extent. The efficacy of COVID 19 vaccines against Omicron variant is decreased with primary vaccination, showing that the vaccine is less efficient in preventing Omicron infections. However, after receiving a booster vaccine dose, the immunological response to Omicron significantly improved and hold promising results. Despite the mild nature of the disease in most vaccinated people, the rapid spread of Omicron, as well as the increased risk of re-infection, poses yet another major public health concern. Therefore, effort should be devoted to maintaining the existing COVID 19 preventive measures as well as developing new vaccination strategies in order to control the fast dissemination of Omicron.
自新冠病毒出现以来，正宗的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）已演变成一系列更受全球关注的新型变体。2021年11月下旬，奥密克戎（谱系B.1.1.529）变体被确定为一种新变体，并被视为第五种受关注变体。奥密克戎具有极其不寻常的基因特征，有大量突变。三十多个突变位于刺突（S）蛋白中，而其他一些突变则存在于其他结构蛋白和非结构蛋白中。S蛋白中的突变有一半位于受体结合域（RBD），这是抗体的主要靶点，表明奥密克戎突变可能会影响抗体与S蛋白的结合亲和力。已发现奥密克戎变体可导致免疫逃逸、治疗或疫苗逃逸，以及传播性增加和再感染风险，这解释了其在国际上的迅速传播，引发了比此前报告的变体更严重的全球警报。奥密克戎有能力绕过先前感染或接种疫苗所诱导的至少一些多方面免疫反应。它被证明能广泛逃逸中和抗体，同时在较小程度上逃避细胞介导的免疫防御。新冠疫苗对奥密克戎变体的效力在初次接种时会降低，这表明该疫苗在预防奥密克戎感染方面效率较低。然而，在接种加强针后，对奥密克戎的免疫反应显著改善并呈现出有希望的结果。尽管在大多数接种疫苗的人中该疾病症状较轻，但奥密克戎的迅速传播以及再感染风险的增加，构成了另一个重大的公共卫生问题。因此，应致力于维持现有的新冠预防措施，并制定新的疫苗接种策略，以控制奥密克戎的快速传播。
