A new Covid variant nicknamed “the kraken” has been dubbed “one to watch this year” as experts warn it could become the next dominant strain in the UK.
The World Health Organisation (WHO) has said the strain is the “most transmissible” strain yet and is thought to be capable of evading immunity built up from vaccines or past infection.
The Kraken - officially named XBB.1.5 - is a “sub lineage” of the Omicron variant known as BQ.1, which is currently the dominant variant in the UK. Experts believe it is not more dangerous than the original Omicron strain but it - along with another variant from the ‘Omicron family’ known as “Orthrus” (CH.1.1) - does have a “growth advantage” which means it could spread more quickly.
A new technical briefing from the UK Health Security Agency (UKHSA) states that XBB.1.5 currently “remains at very low prevalence in the UK, so estimates of growth are highly uncertain”, but it adds: “CH.1.1 and XBB.1.5 are currently the variants most likely to take over from BQ.1 as the next dominant variant in the UK, unless further novel variants arise.
Neither strains have yet been designated as variants of concern by UKHSA, but the health agency said it is “monitoring the situation”.
Concern about Kraken is largely due to how rapidly it has been spreading in the United States. It now accounts for more than 40% of Covid cases in America, according to recent data releases from the Centers for Disease Control and Prevention (CDC), and it has been detected in at least 35 countries - including the UK.
What symptoms does the Kraken variant cause?
Symptoms of the Kraken variant have so far been reported to be very similar to those caused by the previous Omicron strains, although some effects are less common.
Dr Allison Arwady, the Chicago Department of Public Health commissioner, told a US press conference on 3 January that despite being a new mutation, Kraken symptoms have not massively changed because it is a descendant of the Omicron variant.
But she did note that people are predominantly reporting having “cold-like symptoms”, which typically includes a runny nose, sore throat, a cough and congestion. Flu-like symptoms, such as a high fever and feeling sick, are much less common by comparison.
Dr Arwady said: “We’re seeing more people actually just have cold-like symptoms, but [people] are less likely to have those flu-like, really feeling very sick [symptoms such as] the high fevers.”
She added that this is especially the case among people who have had the Covid vaccine, or have built up some immunity from having tested positive for coronavirus in the past.
The ZOE Covid Study, which keeps track of dominant Covid symptoms based on reports to its app by users, has previously warned that there may be some differences in symptoms between people who are vaccinated and those that are not.
More widely, the most common Covid symptoms to look for at the moment, according to the ZOE Health Study, include:
- Sore throat
- Runny nose
- Blocked nose
- Cough (no phlegm)
- Cough (with phlegm)
- Hoarse voice
- Muscle aches
- Altered smell
Health experts say that vaccines remain “the best defence” against severe illness from Covid and future outbreaks.
Dr Meera Chand, director of clinical and emerging infections at the UKHSA said: “Through our genomic surveillance we continue to see evolution of variants in the Omicron family. UKHSA is constantly monitoring the situation and working to understand the implications for public health.
“Vaccination remains our best defence against future Covid-19 waves, so it is still as important as ever that people come forward and take up all the doses for which they are eligible as soon as possible.”