The SARS‐CoV‐2 Omicron Variant and its Multiple Sub‐lineages: Transmissibility, Vaccine Development, Antiviral Drugs, Monoclonal Antibodies, and Strategies for Infection Control – a Review

Abstract

The Omicron (B.1.1.529), fifth variant of concern (VOC) of SARS-CoV-2, initially identified following a steep increase in COVID-19 cases in Southern Africa in November 2021. It is a highlymutated variant and is more contagious as compared with the Delta variant, however less deadly. Due to its high transmission rate, it spreads dramatically, and causing huge surges worldwide. It causes "mild infection", with hospitalisations less likely to occur. However, this variant is known to show resistance to neutralizing antibodies (nAbs) generated through vaccination and/or prior infection as well as to monoclonal antibodies (mAbs) used to treat COVID-19 patients. In many countries, booster doses of vaccines have been recommended to increase the protective levels of antibodies in vaccinated individuals. Along with the implementation of appropriate prevention and control strategy measures, current efforts are also focussed on the development of better vaccines and mAbs to counter this variant. This review highlights the global health concerns and challenges posed by the Omicron variant and present an update on its sub-lineages.

COVID‐19 vaccines and their underbelly: Are we going the right way?

“…However, further evidence of vaccine safety remains to unravel. Emerging SARS‐CoV‐2 mutants could capably escape neutralizing antibodies rendering the over‐the‐counter vaccines ineffective 36–38 . Analysing mutation patterns to facilitate developing mutant‐proof, next‐gen vaccines against variants seem to be even more rational.…”

Characteristics of SARS-CoV-2 Omicron BA.5 variants in Shanghai after ending the zero-COVID policy in December 2022: a clinical and genomic analysis

“…Currently, the Omicron variant (B.1.1.529) is the predominant VOC around the world, since its emergence in South Africa in November 2021 ( Petersen et al, 2022 ). From a genomic perspective, it shares several mutations with the previously identified VOCs, such as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2), but it also harbors a large number of specific mutations ( Mohapatra et al, 2023 ). Up to now, a series of Omicron sub-lineages including BA.1 (original Omicron), BA.2, BA.3, BA.4, BA.5, and XBB have emerged and then caused the waves of COVID-19 globally due to further neutralization escape ( Ai et al, 2022 ; Khan et al, 2022 ; Planas et al, 2022 ; Qu et al, 2022 ; Mohapatra et al, 2023 ).…”

Analyzing the emerging patterns of SARS‐CoV‐2 Omicron subvariants for the development of next‐gen vaccine: An observational study

“…BA.1, BA.2, and BA.3 of these variants were responsible for the fourth wave of the epidemic 3 . New lineages BA.4 and BA.5 emerged quickly thereafter displacing the earlier ones 4 . In July 2022 the sublineage BA.2.75, nicknamed as “Centaurus,” was identified in India 4,5 .…”

“… 3 New lineages BA.4 and BA.5 emerged quickly thereafter displacing the earlier ones. 4 In July 2022 the sublineage BA.2.75, nicknamed as “Centaurus,” was identified in India. 4 , 5 BA.4.6, another sublineage emerged almost simultaneously in many countries.…”

“… 4 In July 2022 the sublineage BA.2.75, nicknamed as “Centaurus,” was identified in India. 4 , 5 BA.4.6, another sublineage emerged almost simultaneously in many countries. Many lineages and sublineages of this rapidly transmitting and highly severe superinfectious Omicron are listed in the “VOC lineages under monitoring” (VOC‐LUM) category by the WHO which are being monitored.…”