The latest offshoot of the virus that causes COVID-19 is cause for caution, according to public health experts — and it has a fitting nickname to go along with that message.

On Jan. 4, the World Health Organization (WHO) declared the XBB.1.5 sub-variant of the Omicron strain of the SARS-CoV-2 virus, which causes COVID-19 — also known as ‘Kraken’ — as the most transmissible seen to date and officials are working to gauge what its impact might be in the broader population.

“It does sound scary, doesn’t it, when we talk about something with the name like the ‘Kraken?’” asked Dr. Nicola Mercer, the medical officer of health for Wellington-Dufferin-Guelph.

The nickname comes from a community of scientists who have agreed to a naming scheme for the growing lineage of the Omicron strain, and a University of Guelph professor appears to have coined the name ‘Kraken’ for the latest strain.

The community of professional and citizen scientists agreed to begin nicknaming sub-variants after mythological creatures to keep in line with the WHO’s naming system using the Greek alphabet to identify new variants.

“Kraken’s not actually Greek, it’s Scandinavian, but it’s pretty common in popular culture,” said T. Ryan Gregory, a professor of evolutionary biology at the University of Guelph. “‘Release the Kraken,’ from the campy 1980’s movie [Clash of the Titans] is what comes to mind for me, the Seattle Kraken hockey team, there’s a rum that’s popular.”

Gregory says scientists are using social media to give nicknames to new sub-variants as an educational tool to better communicate and discuss the different features of emerging versions of the virus.

“It’s got people talking about variants again, which I think is very useful,” said Gregory.

‘Kraken’ followed ‘Griffin’ and ‘Hippogriff’ among a slew of other fantastical nicknames.

“XBB.1.5 seemed to be different. It has certain properties that make it very notable. It’s very good at evading immunity and binding to cells and getting into cells, and that combination really hasn’t been seen at that level before,” said Gregory. “I just said, ‘This one obviously needs a nickname.' It seemed fitting, you know? It would probably be memorable because we were thinking we’d be talking about this for a fair bit, which is obviously the case.”


While the nickname has piqued interest, its traits are more concerning.

The virus is highly transmissible and can evade immunity to spread quickly but, Dr. Mercer doesn’t think Kraken’s transmissibility will necessarily lead to a repeat of the wave created by Omicron’s arrival.

“Maybe, or maybe not,” said Dr. Mercer. “Think about the differences a year ago. We’re a much more vaccinated population, especially in our long-term care retirement homes, and locally, if you’re over the age of 80 or even over the age of 70, we have pretty high and good rates of recent COVID immunization, so those are all variables that we didn’t have a year ago.”

The strain has quickly become the dominant version of the virus circulating in the U.S. and has now been detected in Canada. That’s creating fresh concern for overstrained hospitals which continue to see high patient volumes.

“We’ve had more COVID cases in hospital than influenza and RSV combined,” said Dr. Mercer. “It is still the number one thing that is causing people to stay in hospital.”

In an email to CTV News, Region of Waterloo Public Health described the local COVID-19 situation as “stable.”

Zahid Butt, an Assistant Professor at the School of Public Health Sciences at the University of Waterloo, says the Kraken’s ability to change that stability remains to be seen.

“My concern is more about whether this variant causes severe disease or not, whether it would cause more death,” said Butt. “It’s not just the transmissibility. It’s the impact of the new variant on the health of the population.”

Dr. Mercer adds the spread underscores the need for vaccination, stressing those who haven’t had a booster in the last six months are most at risk of infection and severe outcomes.


When it comes to the efficacy of vaccines against Kraken, experts aren’t expecting currently-approved immunizations to work as well against the sub-variant as other strains of Omicron they were designed to combat.

However, Dr. Mercer stresses getting a booster is better protection than not getting a shot.

“Any vaccination is better than having none because there is some protection,” said Dr. Mercer. “If you get the strain exactly right, it’s obviously the best protection, but if we get it close, it still provides you some significant protection from hospitalization and severe disease; maybe not from getting symptomatic disease but from getting really sick.”

Public Health Ontario continues to recommend vaccination in addition to personal protective measures like mask-wearing, hand hygiene and physical distancing.


Gregory addressed the online criticism of the naming scheme, particularly the use of ‘Kraken’, which may be a form of fear-mongering concerning the virus.

“I have to say, there’s this fear about names like that causing panic. I think the public is a lot more able to distinguish information about these things and is not so prone to panic that calling it ‘Kraken’ is going to cause panic,” said Gregory.

Gregory points to the nickname as a tool that’s proved useful in communicating more effectively about a very complex situation to the broader public.

“If it leads to some people paying more attention and getting the booster they were neglecting to do and wearing a high-quality mask properly when they’re in a situation where that’s warranted, thinking about ventilation, air filtration, testing, isolating if they can, avoiding large indoor gatherings where possible — if that’s the kind of stuff it prompts. I mean, that is the advice that is coming from official public health,” said Gregory.

The Guelph professor likens the naming scheme to the scientific naming of animal species, noting there are technical names and common names for the same creature under a single family tree — like mammals.

“I am somewhat concerned with the idea that it’s all Omicron. I think that particular thing is a misleading claim. The amount of diversity we see within Omicron is enormous. It’s like saying, ‘It’s all mammals,’” said Gregory. “Well, a bat and a shrew and a whale are all mammals, but they’re pretty different.”

Gregory adds there are 650 identified lineages of the Omicron strain of SARS-CoV-2, of which XBB.1.5 — or Kraken — is one.