When compared to other VOC, Omicron has a lot of information, yet it’s still scarce. 1.?Introduction The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that emerged from Wuhan, China in December 2019 posed a significant threat to the global public health (Yang et al., 2020, Guan et al., 2020). COVID-19 causes a variety of symptoms, including fever, dry cough, and shortness of breath, muscle pain, fatigue, sore throat, and anosmia. After emerging of Covid-19, various mutations occur in the virus resulting in various mutant strains like alpha, beta and delta variants. About 23 months since the first reported case of COVID-19, on 24 Nov 2021, a new SARS-CoV-2 variant of concern (VoC), omicron was SR 3576 reported in South Africa. B.1.1.529 was discovered in specimens taken in Botswana on November 11, 2021, and in South Africa on November 14, 2021(Organization WHO, 2021a). Based on the recommendation from World Health Organizations Technical Advisory Group on Virus Evolution, World Health Organization assigned variant B.1.1.529 as a variant of concern (VOC) on November 26, 2021, and named the strain Omicron. The Omicron variant is a highly divergent variant with a large number of mutations, including 26C32 in the spike protein, some of which are concerning and may be linked to humoral immune escape potential and increased transmissibility and it is considered as the most mutated strain among SARS-CoV2, including VOCs and VOIs. Four structural proteinsSpike (S), Envelope (E), Membrane (M), Nucleocapsid (N) proteins, and nonstructural proteins SR 3576 (NSPs) (NSP3, NSP4, NSP5, NSP6, NSP12, NSP1)all have the amino acid alterations of the Omicron variant (Gu et al., 2021). The Omicron variant had been identified in 89 countries across all six WHO regions as of December 16, 2021. B.1.1.529 had spread to 105 countries as of January 10, 2021. According to the WHO, as of November 28, 2021, there is no indication that the symptoms associated with Omicron are unique from those linked with other variants. The condition’s severity, as well as its specific indications and symptoms, are yet unclear (WHO, 2021). The Omicron variation has been detected in 188 nations as of 31 March 2022 and had already become the dominant strain on a worldwide scale, contributing for 99.7% of registered sequences from 23 February to 24 March 2022 (Guo et al., 2022). Four sub lineages of the Omicron variety have emerged: BA.1, BA.1.1, BA.2, and BA.3. The most prevalent Omicron variants in circulation are BA.1, BA.1.1, and BA.2. S-gene target failure may be used to determine the Omicron BA.1 variant, commonly referred to as the original form. BA.1.1 is a sub-lineage of BA.1 with Rabbit polyclonal to Wee1 an R346K alteration in the spike protein. Notably, the fraction of BA.2, which does not produce SGTF, is increasing, and the Omicron BA.2 variants has become prominent in several nations, including Denmark, India, Norway, and Singapore, indicating that it may have a selection advantage over the Omicron BA.1 variant. According SR 3576 to one epidemiological research conducted in Denmark, the effective reproduction number of BA.2 was approximately 1.26 times more than that of BA.1 (Guo et al., 2022). Although BA.1 is expanding more quickly than BA.2, BA.2 has gained ground in a number of countries from January 2022. The BA.2 lineage’s spike protein has a different genetic sequence than the BA.1 lineage, indicating that it may give stronger immunological tolerance to antibodies (Yamasoba et al., 2022a; Wang et al., 2022; Desingu et al., 2022). As more data becomes available, our understanding of the Omicron variant continues to evolve. There is strong evidence that Omicron has a significant growth advantage over Delta. In countries with documented community transmission, it spreads significantly faster than the Delta variant, with a doubling time of 1 1.5C3 days. Omicron is rapidly spreading in countries with high levels of population immunity, and it is unclear how much of the observed rapid growth rate can be attributed to immune evasion, intrinsic increased transmissibility, or a combination of the two. However, based on current data, Omicron is likely to surpass Delta SR 3576 in the case of community transmission. The Omicron variant of SARS-CoV-2 infects cells that depend on its obligatory receptor-angiotensin-converting enzyme 2. (ACE2) (Guo et SR 3576 al., 2022). The S1 and S2 subunits, as well as furin protease cleavage sites, are present in the SARS-CoV2 spike protein. The N-terminal domain (NTD) and receptor-binding domain make up the S1 subunit (RBD). The receptor-binding motif (RBM) directly interacts with the angiotensin-converting enzyme-2 (ACE2) receptor.