WHO declares Delta a new Variant of Concern (VOC)

On May 11, 2021, the WHO classified the variant (B.1.617.2), first identified in India in October 2020, as a Variant of Concern (VOC), after 6 weeks of being a Variant of Interest (VOI). [2]

From May 31, this VOC was referred to by the Greek letter “Delta”, and is said to be “the current dominant variant circulating globally”, that spreads more easily than earlier strains of the SARS-CoV-2 virus and “is responsible for more cases and deaths worldwide” according to WHO. [1]

Determined from genomic sequencing, the lineage B.1.617 contained three sublineages of B.1.617.1, B.1.617.2, and B.1.617.3, and sublineage B.1.617.2 was designated as VOC because its transmissibility was assessed to be at least equivalent to that of the Alpha variant. [3, 4]