Emergence of SARS-CoV-2 Omicron (B.1.1.529) variant, salient features, high global health concerns and strategies to counter it amid ongoing COVID-19 pandemic

Abstract

Since the appearance in the late of December 2019, SARS-CoV-2 is rapidly evolving and mutating continuously, giving rise to various variants with variable degrees of infectivity and lethality. The virus that initially appeared in China later mutated several times, wreaking havoc and claiming many lives worldwide amid the ongoing COVID-19 pandemic. After Alpha, Beta, Gamma, and Delta variants, the most recently emerged variant of concern (VOC) is the Omicron (B.1.1.529) that has evolved due to the accumulation of high numbers of mutations especially in the spike protein, raising concerns for its ability to evade from pre-existing immunity acquired through vaccination or natural infection as well as overpowering antibodies-based therapies. Several theories are on the surface to explain how the Omicron has gathered such a high number of mutations within less time. Few of them are higher mutation rates within a subgroup of population and then its introduction to a larger population, long term persistence and evolution of the virus in immune-compromised patients, and epizootic infection in animals from humans, where under different immune pressures the virus mutated and then got reintroduced to humans. Multifaceted approach including rapid diagnosis, genome analysis of emerging variants, ramping up of vaccination drives and receiving booster doses, efficacy testing of vaccines and immunotherapies against newly emerged variants, updating the available vaccines, designing of multivalent vaccines able to generate hybrid immunity, up-gradation of medical facilities and strict implementation of adequate prevention and control measures need to be given high priority to handle the on-going SARS-CoV-2 pandemic successfully.

Keywords: Immune escape; Omicron; Omicron origin; Prevention and control; Vaccine failure; Variant of concern.

Fig. 1

SARS-CoV-2 variant (1) In a closed subgroup of the population, the virus circulates and mutates, which further infects the large population (Naveca et al., 2019); (2) In an immune-compromised individual the virus stays for a more extended period resulting in the accumulation of a more significant number of mutations (Karim et al., 2021); (3) From an infected individual, the virus transmits to animals, where the fast mutation occurs due to heterologous immune system, which could then possibly may infect a healthy human population (Wei et al., 2021); and (4) If one person, infected with two SARS-CoV-2 variants, there is a chance of recombination, and as a result, Omicron managed to gain so many mutations (Le Page, 2021).