On May 10, 2021, the World Health Organization (WHO) designated B.1.617 a variant of concern (VOC), the fourth variant to receive this designation. In just a few weeks, the Delta variant (B.1.617) became the dominant strain across India and spread throughout the world. Researchers suspect the B.1.617 VOC might be (Vaidyanathan, 2021):
- driving the second COVID-19 wave in India
- more transmissible
- slightly better at evading immunity than existing variants
- able to cause more severe disease
Cherian, et al. (2021) identified eight mutations in the B.1.617 virus’s spike protein. Two of these mutations are similar to mutations that have allowed other VOCs to become more transmissible than the original strain isolated in Wuhan China, and a third resembles a mutation that might have allowed the Gamma variant (VOC P.1) to partially evade immunity. These mutations include the common signature mutations D111D, G142D, L452R, E484Q, D614G and P681R in the spike protein coding region, including within the receptor binding domain (RBD).
Using NGS to Detect the Delta VOC
Two of the primary advantages NGS offers over alternative methods of SARS-CoV-2 mutation detection, are identifying new variants and tracking variants rapidly after they are characterized. The COSMOSID® software analysis, included with the NEXTFLEX® Variant-Seq™ SARS-CoV-2 kit, is able to detect and report the Delta VOC. The genomic analysis report below is an example from a sample containing the Delta VOC (B.1.617).
Who. News updates. 5/12/21.
Cherian, S. et al. (2021) Convergent evolution of SARS-CoV-2 spike mutations, L452R, E484Q and P681R, in the second wave of COVID-19 in Maharashtra, India Preprint at bioRxiv https://doi.org/10.1101/2021.04.22.440932.
Vaidyanathan, G. (2021) Coronavirus variants are spreading in India — what scientists know so far. Nature.