Medical experts say the new COVID-19 mutation dubbed “kraken” is the most contagious subvariant of the virus to emerge since the pandemic began — and it’s becoming the dominant strain in the United States.
As cases of this latest subvariant, known as XBB.1.5, surge across the northeastern section of the nation, local physicians are urging Chicago-area residents to get their booster shots and stock up on COVID tests. They are predicting that a wave will soon hit the Midwest.
While the so-called kraken subvariant only accounts for about 7% of cases in Chicago, the city’s top doctor forecast that its prevalence will likely be increasing here in the coming weeks.
“We are seeing the emergence of more infectious omicron subvariants and XBB.1.5. … It is the most contagious of COVID yet,” said Dr. Allison Arwady, commissioner of the Chicago Department of Public Health, during a Facebook Live session earlier this week. “Given prior experience, I expect that this … will probably be getting into the Midwest and Chicago over the next few weeks, and we probably will see an increase in cases.”
The Biden administration on Wednesday extended the COVID-19 public health emergency another 90 days, amid the spread of this highly infectious subvariant; the White House has renewed the COVID emergency declaration every 90 days since January 2020.
Arwady explained that XBB.1.5 is a fusion of two existing subvariants of the omicron variant of the virus. The name “kraken” was coined by a Canadian biology professor, reportedly named after a sea monster from Scandinavian folklore.
“I would be the most worried if we had a new variant of concern, meaning a new letter of the Greek alphabet,” Arwady said.
While the substrain doesn’t appear to make individuals sicker than other forms of omicron, it does seem to be more transmissible, she said.
Cases of XBB.1.5 spiked following the holidays, primarily in Northeastern states, where the CDC estimates the substrain accounts for more than 70% of all COVID cases.
“It went from 4% of sequences to 40% in just a few weeks,” said Dr. Ashish Jha, White House COVID-19 response coordinator, on Twitter last week. “That’s a stunning increase.”
But he added that all evidence suggests that COVID tests work to detect the latest subvariant and that COVID treatments like Paxlovid and molnupiravir “should work fine based on what we know.”
This comes as the nation faces a “tripledemic” this winter season, as rising rates of flu, RSV and COVID collide at the same time.
But Dr. Elizabeth McNally, director of the Northwestern University Feinberg School of Medicine Center for Genetic Medicine, had a generally optimistic outlook about the COVID landscape, noting that “things look much better this year than they did last year at this same time.”
In early January 2022, Illinois saw record highs in COVID cases and hospitalizations; four of the state’s 11 health care regions had a half-dozen or fewer ICU beds available at the time.
The situation is far less dire this year. Chicago remains at medium community levels of COVID, though the western section of Illinois — including the Quincy area and Springfield — have reached high levels, according to the CDC. Chicago most recently reported an average of 349 new cases a day, down from 405 the previous week, and hospitalizations are down slightly from an average of 29 last week to 27 this week, according to city data.
“I don’t think we need to be pressing the panic button since case numbers over the last 14 days have been only modestly up or steady,” McNally said. “It’s true we each may know people who got COVID recently, but many of these people had only mild cold symptoms.”
She explained that the XBB.1.5 subvariant has many differences in its spike protein and other parts of the virus compared with other versions of COVID, “which can render some antibodies less effective at neutralizing it.”
But she added that there “is still a good deal of immunity across the U.S., so that is why many people have only mild symptoms.”
For more vulnerable populations like older Americans and individuals with reduced immunity, she recommended taking greater precautions such as masking when in large crowds or around other people in tight, indoor settings.
Last month, officials in New York and Los Angeles strongly recommended residents wear masks indoors. Chicago officials have said they will issue a mask advisory if the city reaches high levels of COVID, though residents can always opt to wear masks on their own.
Both Arwady and McNally urged Chicago residents to get the bivalent booster shot, which provides best protection against serious illness and hospitalization. The U.S. Food and Drug Administration last month authorized the update booster for children as young as 6 months.
Yet uptake of bivalent booster shots has remained low nationwide, with a little more than 15% of Americans over the age of 5 and about 38% of those aged 65 and older having received an updated booster dose, according to Centers for Disease Control and Prevention data.
Arwady noted that Chicago residents who were unvaccinated have been nearly three times as likely to be hospitalized with COVID as those who were up to date on vaccines and booster shots.
“If you got your original vaccines, that’s wonderful,” she said. “But if you haven’t had a COVID vaccine since Labor Day, you are not up to date and you don’t have the best protection against omicron, and you should come up to date.”
Arwady encouraged residents to order free at-home COVID tests from the federal government at covid.gov/tests. She also offered tips on making indoor air circulation safer during gatherings, from cracking open windows to installing air filtration systems to turning on exhaust fans in bathrooms and kitchens, and leaving them on an hour after guests leave.
“Bringing fresh air into your home helps, even if it’s only a few minutes every hour,” she said.
