Mutational Pattern, Impacts and Potential Preventive Strategies of Omicron SARS-CoV-2 Variant Infection

Abstract

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.

Inflammatory pathways in COVID‐19: Mechanism and therapeutic interventions

“…The latest Omicron variants are more infectious and induce greater immune escape in humans. 397 And Omicron circumvents many mAb drugs, such as imdevimab, casirivimab, bamlanivimab, and etesevimab, and reduces their therapeutic activity. WHO approved vaccines using COVID‐19, such as: mRNA‐1273 (Moderna), BNT16b2 (Pfizer BioNTech), AZD1222 (AstraZeneca), Sinopharm (Beijing), and Sinovac (CoronaVac) against Omicron with humoral immunity and neutralizing titers significantly reduced, which undoubtedly poses a test for the future of COVID‐19 control.…”

“…In addition, the high mutability of SARS‐CoV‐2 and the continuous evolution of new variants pose significant challenges for the detection, prevention, and treatment of COVID‐19. The latest Omicron variants are more infectious and induce greater immune escape in humans 397 . And Omicron circumvents many mAb drugs, such as imdevimab, casirivimab, bamlanivimab, and etesevimab, and reduces their therapeutic activity.…”

“…WHO approved vaccines using COVID‐19, such as: mRNA‐1273 (Moderna), BNT16b2 (Pfizer BioNTech), AZD1222 (AstraZeneca), Sinopharm (Beijing), and Sinovac (CoronaVac) against Omicron with humoral immunity and neutralizing titers significantly reduced, which undoubtedly poses a test for the future of COVID‐19 control. Currently, the main preventive strategies against the Omicron variant are to strengthen public health precautions for timely detection, early detection, and isolation; to enhance immune resistance by developing new vaccination strategies as the original vaccine remains effective against Omicron; and to use or design new monoclonal antibodies, such as the approved Sotrovimab, Paxlovid, Veklury (raltegravir), molnupiravir, and bebtelovimab for the treatment of moderate or severe COVID‐19 patients 397 . This paper suggests that the immunopathogenesis of both SARS‐CoV‐2 and its latest variants is through the induction of a dysregulated inflammatory response that promotes CS, ARDS, and multiorgan damage, and therefore, targeting the initiation of inflammatory signaling pathways and the release of downstream cytokines has important benefits for controlling the disease process and adjuvant therapy.…”

The Experience of COVID-19: Variants, Vaccines and Policies

“…There are three sublineages of Omicron including BA.1 (B.1.1.529.1) which is a standard sub-lineage, BA.2(B.1.1.529.2), and BA.3(B.1.1.529.3) are rare subvariants. The transmissibility of omicron is seven times that of alpha, and one-fifth of all global COVID-19 infections are BA.2 cases [10]. It could, in particular, avoid most of them hitching, rather than all of them, licensed monoclonal antibodies, furthermore interfering with the interaction between ACE2 and spike.…”

Analysis of the genetic diversity of SARS-CoV-2 genomes carrying the Omicron B.1.1.529 mutation

“…This brings us back to the fact that complete vaccination schemes are the main allies in containing all variants and especially the Omicron variant. (Chekol et al , 2022).…”