Release the Kraken!

A highly contagious COVID-19 variant dubbed 'the Kraken,' after the mythical sea monster, has been confirmed in Davidson County and elsewhere in Tennessee as cases of the novel coronavirus continue to rise, public health officials say.

This strain of the virus, known technically as "XBB.1.5," is also now the leading strain of COVID-19 in the United States, accounting for an estimated 43% of confirmed cases, according to the Centers for Disease Control and Prevention. In December, XBB.1.5, accounted for about 10% of U.S. cases, according to the John Hopkins University COVID Resource Center.

In the southeast U.S. region that includes Tennessee, the Kraken strain is the second-most prevalent strain, making up about 31% of all cases, CDC data show. State health officials are encouraging those who have not been vaccinated to do so. Those who are eligible to get the bivalent booster shots should also get them, they say.

"We are continuously monitoring COVID-19 in all its variants and forms," said Bill Christian, spokesman for the Tennessee Department of Health. "Vaccination is our best defense against COVID-19 and protects against severe outcomes, including death."

Christian would not comment when asked which counties have confirmed the presence of XBB.1.5.

The Metro Public Health Department for Nashville and Davidson County confirmed through genetic testing last week that the Kraken variant is circulating locally, said Leslie Waller, an epidemiologist with the Metro Public Health Department.

What's different about XBB.1.5, the so-called 'Kraken' variant?

According to the Johns Hopkins University COVID-19 Resource Center, scientists believe the XBB.1.5 variant (a subvariant of the Omicron variant of COVID-19) has certain mutations that allow it to better bind to cells and, by extension, make it more transmissible. This is likely the reason that it is quickly becoming the dominant strain in the United States.

The World Health Organization has concluded that it's among the most antibody-resistant variants to date, suggesting that case counts may continue to rise in this country.

How likely are people to catch this variant?

Short answer: It depends.

While some sensational headlines have suggested that those who haven't caught COVID-19 yet are likely to catch this particular strain, it really depends on how well people are protected and if they are exposed, Waller said.

"People's immune systems are very different. People have a different combination of vaccines that they've received, ranging from none at all, all the way up to their second bivalent boosters," she said. "And then there are people who have chronic conditions that render their immune systems quite weak."

That said, previous infections don't seem to be a guarantee of protection, especially if they happened a long time ago. Public health experts also expect more infections as more people continue to gather in large crowds or in confined spaces without masks.

Dr. Ashish Jha, who leads the Biden administration's COVID-19 Task Force tweeted earlier this month that people who haven't recently been infected or gotten a bivalent booster "likely have very little protection" against infection.

Johns Hopkins University notes that even someone who has been infected with an earlier omicron variant is "likely susceptible" to an XBB.1.5 infection because natural immunity wanes over time and XBB.1.5 is more transmissible.

Is the 'Kraken' variant more dangerous?

For now, it doesn't seem to be.

The WHO is still assessing XBB.1.5 but notes that it doesn't have any mutations that make people sicker than the other variants.

"It's certainly something to keep an eye on, especially for those who are particularly vulnerable," Waller said. "But, in terms of worry and panic, I don't think that's particularly warranted at this time. There's not currently any indication that it makes people sicker."

Why is it called the 'Kraken?'

The Kraken, a mythological creature of Scandinavian lore often depicted as a giant squid or octopus, got attached to this particular version of COVID-19 reportedly by a biology professor at the University of Guelph in Ontario.

According to Fortune, Dr. Ryan Gregory was looking for a memorable name for variants and was inspired by a Twitter user who had dubbed another variant "Centaur." He came up with Kraken, which quickly picked up steam. Soon, a very click-baity new COVID variant was born.