New Delhi: ‘Kraken,’ or XBB.1.5, a new COVID variant that was first detected last year has quickly become the dominant strain in the US. It has now been identified in at least 28 other countries, according to the World Health Organisation. it has the capability to infect even those who have been vaccinated, according to experts.
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 was quoted as saying by The Free Press Journal.
Dr Jayadevan further explained that this variant has the ability to infect those who had prior infection or even vaccination. “Immune evasiveness is the ability of the virus to infect people who had prior infection or vaccination or both. XBB.1.5 achieved this by creating a rare type of mutation called F486P, located in its RBD (receptor binding domain). It is not known whether it causes more severe diseases. Experts believe it is unlikely to do so,” the expert was quoted as saying.
However, he said that continued vigil is needed to see if these ongoing genetic changes also enable the virus to cause more severe disease.
“The latest genomic surveillance data from India show XBB accounts for 20 per cent, while the older variant BA.2.75 is still dominant. This landscape could change,” he said.
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. The original XBB variant has already caused waves of infection in countries including Singapore and India since the WHO first raised concern about it last October, NDTV reported quoting Bloomberg.
While accounting for just 1% of all COVID cases at the start of December, estimates from the US Centers for Disease Control and Prevention show that it surged to become the dominant strain by the end of the month, responsible for about 41% of all infections. In northeastern states, that figure has jumped above 70%, according to the report.
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 on Jan 4. While only 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. In other countries, the proportion of infections caused by XBB.1.5 has remained lower, although the picture may rapidly change. Estimates from the Wellcome Sanger Institute found that the variant made up around 4% of Covid infections in England as of mid-December, while Canada has found a handful of such cases.
Scientists pointed out that 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.
There is limited data Data on XBB.1.5’s severity and its propensity to cause severe disease or death. Previous therapies to tackle COVID- like monoclonal antibody treatments – were rendered ineffective by previous strains. That trend is set to continue with the new variant. Scientists in a recent peer-reviewed article published in the journal Cell warned that subvariants like XBB pose “serious threats” to current COVID vaccines. Higher transmissibility also means more people are likely to get infected, and thereby suffer severe outcomes.
Where does the name come from?
COVID variants are currently named by an expert group convened by the WHO. It identifies so-called variants of concern that have potential global public health significance, such as reducing the effectiveness of current pandemic measures, using the Greek alphabet. Previous strains like alpha, beta and delta fell under the convention. But the last Greek-named variant, omicron, emerged more than a year ago and left no room for the emergence of other, significantly different strains. Omicron has spawned multiple lineages, including XBB 1.5, and their names stem from a mix of alphabets and numbers known as “Pango.”
That has led to the rise in popularity of informal online nicknames, including “Kraken.” The moniker for XBB.1.5 was proposed by an evolutionary professor on Twitter to match the strength of the new strain with the mythological sea monster, Bloomberg reported.
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