1Department of Natural Sciences, Northeastern State University, Broken Arrow, Oklahoma, USA
2Zonal Microbiologist, Central Railway Hospital (North Western Railway), Jaipur, Rajasthan, India
3Tulsa Community College, Northeast Campus, 3727 East Apache St., Tulsa, OK74115, USA
As the COVID-19 pandemic stretches into an exhausting third year, the viral death toll decreases as the toll on global health and economies increases. COVID-19 virus (SARS-CoV-2) is an mRNA virus. It constantly evolves from its ancestral strain. The SARS-CoV-2 variant-of-concern Omicron (PANGO lineage B.1.1.529) emerged in November 2021 and branched into more transmissible and immunity evasive versions. Novel sublineages differ significantly and meaningfully from the original Omicron variant. Notable Omicron sublineages include BA.1, BA.2, BA.2.12.1, BA.3, BA.4 and BA.5. Currently, BA.2.12.1, BA.4 and BA.5 are causing COVID-19 waves around the globe. Novel recombinant SARS-CoV-2 lineages (XD, XE, XF) derived from Omicron sublineages have also been observed. Emergence of these subvariants has raised urgent questions regarding the capacity of each to evade vaccine-induced immunity or immunity conferred by prior infections. In this article, we present a comprehensive review of Omicron novel subvariants BA.2.12.1, BA.4 and BA.5 with a focus on their ability to evade immunity and severity of disease caused based on updated, empirical data from available sources and publications.
COVID-19, Immunity evasion, Neutralization antibody, Omicron BA.4/5, Vaccine booster, Variant of concern
