A new version of Omicron XBB.1.5 has raised concerns in many countries including India where its cases have been reported, and it has the capability to infect even those who have been vaccinated. XBB.1.5, a highly contagious 'recombinant' variant that spawned from two different BA.2 variants, is spreading in the US. According to World Health Organisation, it’s the most transmissible version of Covid. Nicknamed the 'kraken variant', it surged through the nation and has now been identified in at least 28 other countries.
XBB.1.5 is a descendant of the omicron XBB subvariant - which is itself a cross between two earlier strains: BA.2.75 and BA.2.10.1. According to Dr Rajeev Jayadevan, Co-chairman of the National IMA Covid task force, XBB.1.5 is an upgraded version of XBB, a recombinant sub-lineage of Omicron that was found a few months ago in multiple countries like Singapore and later in India. "XBB.1.5 has a greater ability to attach itself to the human ACE-2 receptor while retaining the outstanding immune evasiveness of its ancestor," he said.
According to data from the US Centers for Disease Control and Prevention (CDC), 41 per cent of cases in the US are attributed to the Kraken. Later, its cases have also been found in parts of Europe, Australia and South East Asia.
How fast is XBB.1.5 or Kraken spreading?
XBB.1.5 is "the most transmissible sub-variant which has been detected yet," said WHO's Covid-19 technical lead, Maria Van Kerkhove, during a press conference. While 29 countries have reported cases caused by it, health authorities are warning it could be much more widespread and silently proliferating thanks to a drop-off in testing.
To note, the sub-variant has a much stronger affinity to ACE2, a key receptor for the virus, which allows it to bind more easily and boosts its transmissibility. Additionally, XBB.1.5 variant is the most transmissible sub-variant that has been detected yet. The variant has been found to be 120 percent faster than the previous BQ1 variant, WHO reported. The variant, however, is being watched closely by the WHO.
On January 3, the SARS-CoV-2 Genomics Consortium (INSACOG) informed that India has a total of five detected cases of the XBB.1.5 variant: three in Gujarat and one in Karnataka and one in Rajasthan.