Divergent mutations of Delta and Omicron variants: key players behind differential viral attributes across the COVID-19 waves

Abstract

The third SARS-CoV-2 pandemic wave causing Omicron variant has comparatively higher replication rate and transmissibility than the second wave-causing Delta variant. The exact mechanism behind the differential properties of Delta and Omicron in respect to infectivity and virulence is not properly understood yet. This study reports the analysis of different mutations within the receptor binding domain (RBD) of spike glycoprotein and non-structural protein (nsp) of Delta and Omicron strains. We have used computational studies to evaluate the properties of Delta and Omicron variants in this work. Q498R, Q493R and S375F mutations of RBD showed better docking scores for Omicron compared to Delta variant of SARS-CoV-2, whereas nsp3_L1266I with PARP15 (7OUX), nsp3_L1266I with PARP15 (7OUX), and nsp6_G107 with ISG15 (1Z2M) showed significantly higher docking score. The findings of the present study might be helpful to reveal the probable cause of relatively milder form of COVID-19 disease manifested by Omicron in comparison to Delta variant of SARS-CoV-2 virus. Supplementary Information The online version contains supplementary material available at 10.1007/s13337-023-00823-0.

An Overview of the Strategies to Boost SARS-CoV-2-Specific Immunity in People with Inborn Errors of Immunity

“…in July 2023 to Omicron E.G.5.1 in December 2023, with the epidemiology differing by geographical location (Figure 1). The current dominant variants have an immune evasion advantage, but result in less severe infections in the general population [38,47]. Here, more observation is needed to determine how variant transmission impacts the IEI community in terms of infection rates and severity of illness.…”

“…For example, the Omicron BA.1 variant, which emerged in November 2021, has 37 spike protein mutations, resulting in increased ACE2 binding affinity and decreased humoral immune recognition [ 45 ]. To date, the Omicron lineage is the most divergent variant due to the high number of mutations it harbors, with all sublineages maintaining properties of increased immune evasion and preference for binding to ACE2 compared to earlier SARS-CoV-2 variants [ 46 , 47 ] ( Table S1 ).…”