Omicron Variant (B.1.1.529) of SARS-CoV-2, A Worldwide Public Health Emergency!

Abstract

B.1.1.529 is the newest form of SARS- CoV-2. It was initially reported to the World Health Organization (WHO) on November 24, 2021, by South Africa. WHO recognized it as a variant of concern on November 26, 2021, and named it "Omicron.” The Omicron variant features an exceptionally large number of mutations, many of which are unique, and a substantial number of which impair the spike protein targeted by most COVID-19 vaccines at the time of its discovery. Despite initial studies showing that the variant caused less serious disease than prior strains, this amount of miscellany has raised worries about its transmissibility, immune system evasion, and vaccine resistance. Omicron is suspected to be much more infectious than previous variants of concerns, spreading around 70 times faster in the bronchi, but it is less able to penetrate deep lung tissue, which may explain why there is a significant reduction in the risk of severe disease requiring hospitalization. Nonetheless, because of the virus's fast rate of transmission and capacity to resist both two-dose vaccination and the immune system, the overall number of patients requiring medical care at present remains a major worry. In this article, the current state of the art for Omicron variant has been discussed to provide a strong framework for future research. The evolution, mutation, epidemiology, infectivity, vaccine breakthrough, and antibody resistance of the Omicron variant are investigated and discussed.

Biological Properties of SARS-CoV-2 Variants: Epidemiological Impact and Clinical Consequences

“…Zeng et al (2021) reported that Omicron has a significantly enhanced efficiency of cell-to-cell transmission, with 4.8-fold higher levels than D614G and other variants [183]. On 8 November 2021, this variant was discovered in South Africa, and within two weeks, more than 70% of sequenced samples from Gauteng province in South Africa were Omicron [299]. By 11 December 2021, the United States had reported that the Omicron variant was responsible for nearly 7% of COVID cases.…”

“…In the next two weeks, this rate quickly increased to around 23% and 60%, respectively [300]. The variant has now been identified in all 50 states and became the dominant variant within just three weeks since its discovery in the United States [299]. On 4 January 2022, the United States alone recorded more than one million cases [301].…”

“…Although approved vaccines have been less effective in preventing infection, they provide considerable protection against Omicron, with booster doses (3X) providing a high level or protection, exceeding 80% under certain circumstances [317]. Based on 132 3D models of RBD antibody complexes, it was reported that Omicron may be twice as likely to evade existing vaccinations compared Delta [299]. Data gathered from 48 healthcare workers (HCWs) in the United States 3-4 weeks after receiving a second dosage of either Moderna mRNA-1273 (n = 20) or Pfizer/BioNTech BNT162b2 (n = 28) revealed that the Omicron had 22.9-fold (p < 0.001) higher neutralization resistance than the ancestral D614G [183].…”

“…Data gathered from 48 healthcare workers (HCWs) in the United States 3-4 weeks after receiving a second dosage of either Moderna mRNA-1273 (n = 20) or Pfizer/BioNTech BNT162b2 (n = 28) revealed that the Omicron had 22.9-fold (p < 0.001) higher neutralization resistance than the ancestral D614G [183]. The sensitivity of 28 serum samples from COVID-19 convalescent patients infected with the original SARS-CoV-2 strain was tested against pseudotyped Omicron, as well as other VOCs (Alpha, Beta, Gamma, and Delta) and VOIs (Lambda and Mu) [299]. According to data from the state of New York, USA (n = 8,834,604), between May and September 2021, Rosenberg et al (2022) reported high vaccine efficacy in preventing severe disease in people over the age of 65, with varying levels of protection conferred by differ-ent vaccines-95% for BNT162b2, 97% for mRNA-1273, and 86% for Ad26.COV2.S-and minimal declines in protection 6 months after vaccination [357].…”

Can the SARS-CoV-2 Omicron Variant Confer Natural Immunity against COVID-19?

“…The Omicron variant is unique in that it contains the most mutations of all SARS-CoV-2 variants ( Figure 4 ). A total of 50 mutations have occurred in this variant [ 66 ]. The envelope (E) protein has one substitution (T9I), the membrane (M) protein has three substitutions (D3G, Q19E, and A63T), and the nucleocapsid (N) protein has three substitutions and a three-residue deletion.…”