Omicron: No clear evidence on increased virulence, finds study

HYDERABAD: A nationwide joint study by researchers, including doctors from AIIMS, Mangalagiri (Vijayawada), has found that though the new Covid-19 variant of concern, Omicron, has higher immune escape ability than the existing variants, there’s no clear indications of increased severity (affinity for ACE2 binding) of the disease.
It will however, outcompete Delta variant. There is currently no clear evidence for increased virulence or lethality for Omicron.
“Omicron may have greater immune escape ability than the existing variants of concern (VoCs) and variants of interest (VoIs). However, there are no clear indications coming out from the predictive mutational analysis that Omicron may have higher virulence/lethality than other variants, including Delta. The higher ability for immune escape may be a likely reason for the recent surge in Omicron cases,” the study based on a computer (in silico) analysis said.
The study was published in preprint online server MedRxiv. According to the study, compared to the current list of VoCs/VoIs Omicron bears more sequence variation, specifically in the spike protein and host receptor-binding motif.
Omicron showed the closest nucleotide and protein sequence homology with Alpha variant for the complete sequence. The mutations were found primarily condensed in spike region (28 to 48) of the virus.
The team performed a correlation analysis of the relative proportion of genomic sequences of specific variants (from October 1 to December 10), with current epidemiological data (new Covid cases and deaths) from South Africa to understand whether Omicron has an epidemiological advantage over other variants.
As many as 3,604 genomic sequences of Omicron from 54 countries were uploaded on GISAID until December 10 and the team had analysed them for the mutational characteristics. Omicron showed more sequence variation including spike protein receptor binding domain.