Since the SARS-CoV-2 variant known as B.1.617 was first reported in India late last year, it has spread to dozens of other countries — including the United States, Singapore and the United Kingdom, where it has become dominant in some regions.
Researchers have since identified three subtypes, known as B.1.617.1 (the ‘original’ B.1.617), B.1.617.2 and B.1.617.3, each with a slightly different genetic make-up.
They are now rushing to investigate these variants and work out how they might affect the trajectory of the pandemic in countries where they have gained a foothold. Key questions remain about how quickly the variants can spread, their potential to evade immunity and whether they cause more severe disease.
A lot of this research takes the form of standard epidemiology — confirming COVID-19 cases through testing, identifying the variants responsible for infections and cross-referencing these data to people’s clinical symptoms and vaccination statuses. Scientists can also glean insights from genomic-sequencing data, identifying which mutations are present in the B.1.617 subtypes and comparing these with mutations in earlier variants whose behaviour is better understood.