Even as the Omicron variant of SARS CoV-2 exhibited diminished fusogenicity and pathogenicity compared with the Delta variant and the parental virus, a recent study investigating the effect of L452R, a mutation seen in the Delta variant, on the fusogenicity of the Omicron variant, and published on Nature.com, demonstrated that the combination (Omicron-L452R) exerted markedly enhanced fusogenicity and thereby it could be one of the most riskier variants.  This is because the essential role of the L452R mutation in SARS-CoV-2 was fusogenicity and infectivity.