Covid-19 Q&A: What you need to know about the new variant they’re calling Kraken

Dr Muiris Houston looks at the latest variant of Omicron and the challenges it poses

What’s the story on this new version of Covid-19 they’re calling Kraken?

It’s the latest variant of Omicron with the World Health Organisation-approved name XBB.1.5. It’s directly descended from the Omicron BA.2 version that has been circulating in Ireland over recent months. Some global experts say there is a need to move on from the Omicron nomenclature and they have unofficially named XBB.1.5 as “Kraken”. The name has its origins in Greek mythology, where Kraken is described as a sea monster of large size and strength.

How widespread is the Kraken variant?

It has been recorded right across Europe and has taken a particular hold in the northeastern United States. Because there is so little testing being carried out in Ireland, it is difficult to put an exact figure on its prevalence here. The latest figures from the Health Protection Surveillance Centre, relating to the pre-Christmas period, put the number of Kraken-positive tests at four.

What’s different about XBB.1.5/Kraken?

It is quickly spreading, at a greater rate of any variant, since Omicron BA1 a year ago. XBB.1.5 is a recombinant virus – a mixture of two spin-offs of Omicron BA.2. The new variant’s extreme transmissibility is due to its high level of immune escape (its ability to evade our immune systems, even when they have been primed by previous infection or vaccination). The new strain also binds extra well to the cells it infects.

Does it cause more hospitalisations and deaths compared with previous Omicron variants?

The jury is still out on this. We need to see more data from the European Centre for Disease Prevention and Control and the US Centres for Disease Control and Prevention to determine XBB.1.5′s lethality and illness severity.


Will the new Omicron bivalent booster vaccine protect me from the Kraken variant?

It is too soon to tell with certainty. Some experts have speculated that protection against XBB.1.5 is not great for people who were last infected with Covid before July 2022 and who haven’t received the new bivalent booster.

I’m finding it hard to keep up with the ever-lengthening chain of Omicron variants. Can we not move on to labelling a new variant as Pi, the next letter in the Greek alphabet?

You are not the only one who finds the nomenclature tedious and confusing. The WHO moves slowly, however, and is still considering the issue. So far, it maintains the new variants aren’t sufficiently different to warrant moving further along the Greek alphabet. The Canadian biology professor, Dr Ryan Gregory, who named the latest variant “Kraken”, told Fortune magazine that sticking with Omicron “just isn’t cutting it anymore”.

He now leads an informal group of scientists who believe the time has come to offer “street names” for complicated Covid strains, in a bid to better communicate the evolving Omicron threat to the public. Gregory and his colleagues have compiled a list of monikers from Greek mythology for use as new Omicron variants emerge. Look out for names like Chiron, Argus and Typhon hitting the headlines in the absence of movement by the WHO on the naming issue.