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Review
. 2022 Dec 1;30(4):480-494.
doi: 10.53854/liim-3004-2. eCollection 2022.

The emergence of SARS-CoV-2 Omicron subvariants: current situation and future trends

Ramadan Abdelmoez Farahat  1 , Abdelaziz Abdelaal  2   3   4 , Tungki Pratama Umar  5 , Amro A El-Sakka  6 , Amira Yasmine Benmelouka  7 , Khaled Albakri  8 , Iftikhar Ali  9 , Tareq Al-Ahdal  10 , Basel Abdelazeem  11   12 , Ranjit Sah  13   14 , Alfonso J Rodriguez-Morales  15   16   17   18
Affiliations
Review

The emergence of SARS-CoV-2 Omicron subvariants: current situation and future trends

Ramadan Abdelmoez Farahat et al. Infez Med. .

Abstract

The SARS-CoV-2 Omicron variant (B.1.1.529) has been the most recent variant of concern (VOC) established by the World Health Organization (WHO). Because of its greater infectivity and immune evasion, this variant quickly became the dominant type of circulating SARS-CoV-2 worldwide. Our literature review thoroughly explains the current state of Omicron emergence, particularly by comparing different omicron subvariants, including BA.2, BA.1, and BA.3. Such elaboration would be based on structural variations, mutations, clinical manifestation, transmissibility, pathogenicity, and vaccination effectiveness. The most notable difference between the three subvariants is the insufficiency of deletion (Δ69-70) in the spike protein, which results in a lower detection rate of the spike (S) gene target known as (S) gene target failure (SGTF). Furthermore, BA.2 had a stronger affinity to the human Angiotensin-converting Enzyme (hACE2) receptor than other Omicron sub-lineages. Regarding the number of mutations, BA.1.1 has the most (40), followed by BA.1, BA.3, and BA.3 with 39, 34, and 31 mutations, respectively. In addition, BA.2 and BA.3 have greater transmissibility than other sub-lineages (BA.1 and BA.1.1). These characteristics are primarily responsible for Omicron's vast geographical spread and high contagiousness rates, particularly BA.2 sub-lineages.

Keywords: BA.2 sub-lineages; COVID-19; Omicron variant; SARS-CoV-2; immune evasion; spike protein; transmissibility.

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Conflict of interest statement

Declaration of competing interest Authors have no conflict of interest, except AJ Rodriguez-Morales, speaker/consultant for Amgen, AstraZeneca, and Valneva, concerning COVID-19 vaccines.

Figures

Figure 1
Figure 1
The number of recent omicron variant cases globally as of October 19, 2022. This original figure was developed based on data available on the GISAID initiative [8].
Figure 2
Figure 2
General scheme of Omicron variant of SARS-CoV-2. Twenty-one common mutations.
Figure 3
Figure 3
General scheme of Omicron variant of SARS-CoV-2. Twenty-one common mutations are found in the spike protein shared between each subvariant.
Figure 4
Figure 4
COVID-19 cases between September 13 and October 17, 2022, in selected countries of Europe.
See this image and copyright information in PMC

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