A highly contagious "recombinant" variant composed of two different BA.2 strains, the "kraken" variant has quickly become the dominant form of COVID in the U.S. and is continuing to spread nationwide.
Also known as XBB.1.5, the variant quickly rose to prominence as experts say it is more contagious than many of its predecessors.
"It went from 4% of sequences to 40% in just a few weeks," Dr. Ashish Jha, White House COVID czar, tweeted last week. "That’s a stunning increase."
Jha said the variant is likely more immune evasive, even "more than other omicron variants."
Dr. Allison Arwady, commissioner of the Chicago Department of Public Health, echoed that sentiment.
She said the variant is "clearly more infectious" than other variants, "meaning it's spreading more easily" and "outcompeting the other variants."
Currently, the variant is surging largely in the Northeast, where it makes up more than 75% of cases. Nationwide, the strain makes up approximately 40% of cases, however, the numbers are much lower in the Midwest, with it accounting for just 6% of cases.
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Arwady noted symptoms haven't changed with the new variant, though she noted that symptoms similar to the flu are less common, particularly in those who are vaccinated and boosted.
"COVID is showing up very much like it already has. I think, if anything, we are seeing it a little bit less likely to have the more severe symptoms," Arwady said. "Definitely people get the severe symptoms still, especially if they're not up-to-date with their vaccines. But more often now we are seeing people - especially if they're fully up-to-date, maybe it's their second time getting COVID, whatever it might be - we're seeing more people actually just have cold-like symptoms, less likely to have those flu-like, really feeling very sick, the high fevers."0
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Jha, the head of the White House COVID Task Force, addressed a number of points about XBB.1.5 in a lengthy Twitter thread last week.
He stressed that if you had an infection before July or were last vaccinated prior to the bivalent update in September, "Your protection against an XBB.1.5. infection is not that great."
The strain's rapid rise in dominance has led some experts to question whether or not the variant will lead to added concerns in the weeks following holiday gatherings, with COVID hospitalizations already rising in the U.S.
While it's not clear where the variant originated exactly, Arwady said it has so far not shown signs of leading to more severe infections.
"They are seeing some increase in hospitalizations in older folks in the Northeast, but that seems to be at least based on what you know, I'm reading and hearing from folks, that seems to be based as much on the fact that they're seeing just a surge overall... and so with that increase, it seems like we're just seeing more older people get infected and if they're not up-to-date, especially with their vaccines, they are somewhat more likely to be hospitalized," she said during a Facebook Live last week. "But no, I haven't seen anything suggesting that this new subvariant is clearly making people sicker. I think we'll learn more as we follow it."
Arwady noted that while there are significant concerns surrounding the new strain, it remains an omicron subvariant, which offers less risk than if the variant were in an entirely different family.
"It's in that variant of interest category. We label it, we monitor it, we give it those those alphabet soup of letters to be able to keep track of it, but the big worry is if we see something emerge and grow to be a new variant of concern, meaning it gets a new letter in the Greek alphabet," she said. "We haven't had one of those in a year. I hope we never have one again."
