The Kraken COVID-19 variant accounts for almost 41 per cent of all Covid infections.
Kraken -- the nickname for the XBB.1.5 SarsCoV-2 variant -- is spreading fast across the globe and has already been detected in 29 countries.
While the World Health Organisation has expressed concern about the variant, experts in India see no reason for alarm yet.
"Truly there is no way we can guess the severity from communicability," says Dr Jayaprakash Muliyil, epidemiologist at CMC Vellore and member of the working group of the National Technical Advisory Group. "For that, we need to see information on hospitalisation and case fatality."
"At present, the information suggests that this Omicron is very similar to previous ones in severity. Do stay calm," says Dr Muliyil.
The XBB.1.5 variant is a cross between BA.2.75 and BA.2.10.1. It is a descendant of the Omicron XBB variant.
Like all XBB variants, XBB.1.5, too, has spread fast.
Data from the US Center for Disease Control and Prevention shows that from just 1 per cent of the COVID-19 cases in the US in December 2022, the Kraken variant now accounts for almost 41 per cent of all Covid infections.
It has been dubbed as 'the most transmissible sub-variant detected yet by WHO's Covid technical lead, Maria Van Kerkhove.
Experts caution that this fast-spreading variant can impact health care systems.
Dr Shahid Jameel, senior research fellow at Green Templeton College at Oxford University, says the XBB.1.5 will spread more than its predecessor.
"It's already become the dominant variant in the US -- from 4 per cent to 40 per cent in a short period of time. It's still Omicron, so nothing changes in terms of severity in vaccinated and hybrid immune populations," says Dr Jameel, who adds, "We should not worry, but stay cautious.
"Very large number of infections can impact health care systems and can lead to higher-than-expected severe outcomes."
Global experts have pointed out that this particular sub-variant has a much stronger affinity to a key receptor ACE2, which allows it to bind more easily to human or host cells, making it highly transmissible.
Senior viologist Dr Gagandeep Kang says it seemed to be more transmissible in the US, but not increasing at the same rate elsewhere.
So far, there has been no noted change in severity of the disease caused by this particular variant.
"Treatments that were tried during the Delta-wave -- like monoclonal antibody treatments -- are unlikely to be effective for Omicron sub-variants. This is already seen. So even for Kraken, these therapies are unlikely to be effective," says the MD of a biotech firm.
"Hybrid immunity from vaccines and past infections is our best bet against these new sub-lineages of Omicron," he adds.
How did the Kraken name come about?
Typically, COVID-19 variants are named by an expert group at WHO, which identifies the variants of concern across the globe.
The names are taken from Greek alphabets -- alpha, beta, delta, etc.
Omicron has been the dominant COVID-19 variant for one year, and it has several sub-lineages, which are a mix of alphabets and numbers known as 'Pango'. XBB.1.5 is one such name.
The Pango dynamic nomenclature is a popular system for classifying and naming genetically distinct lineages of SARS-CoV-2, including variants of concern, and is based on the analysis of complete or near-complete virus genomes.
According to Bloomberg, the moniker Kraken 5 was proposed by an evolutionary professor on Twitter to equate the strength of the new strain with the mythological sea monster.
Kraken is a legendary sea monster of enormous size said to appear off the coasts of Norway.
Complicated Pango lineage names may have led to giving informal names to these emerging sub-variants of Omicron.
Feature Presentation: Ashish Narsale/Rediff.com
