What is the Kraken COVID variant, and what’s with the monster nicknames?

XBB.1.5, a new subvariant of COVID-19 that was first detected in October, is now ripping through the northeastern United States, up from nothing a month ago, but now doubling its share of total cases in a week. It is in Canada and two dozen other countries. Concern is high about its rapid and efficient spread, but it does not seem to cause especially bad disease. The National Post’s Joseph Brean runs down the latest details on the Kraken variant, as it is being called.

It is the nickname for a worrying new subvariant of the Omicron strain of COVID-19. “It is on the increase in the U.S. and Europe and has now been identified in more than 25 countries,” said World Health Organization Director General Tedros Adhanom Ghebreyesus on Wednesday, Jan. 4. The WHO’s Technical Advisory Group on Virus Evolution says the “rapidly increasing proportion of XBB.1.5 in the United States and other countries” is an urgent concern and it is preparing a new update in the next few days. The BC Centre for Disease Control says there have been five reported cases of the latest strain as of Tuesday.

A main concern is the speed at which it spreads compared to other subvariants. Cases are surging in the U.S. As of this week, Kraken represented more than 40 per cent of cases in the U.S. The week before that, it was half that figure, and just the third most common variant. At the beginning of December it barely registered at 1 per cent. And in places where it is currently spreading, mainly in the northeast of the U.S., it accounts for almost three cases in every four. That speaks to a subvariant that spreads efficiently despite the accumulated immune protections from vaccines and previous infection with other subvariants. Immunologists call this “immune evasive.”