A new COVID-19 sub-variant called “Arcturus” has emerged in some parts of the world.
A risk assessment released by the World Health Organisation (WHO) said the first report of the strain – a sub-variant of Omicron – was made on 9 January 2023, with the variant under investigation since 22 March.
As of 17 April 2023, it has become a “variant of interest” (VOI) after cases were reported from 33 countries – with most coming from India.
Other countries where the variant has also been detected include the US, Singapore, Australia, Canada, Brunei, Japan and the UK.
However, the WHO said the “global risk assessment for XBB.1.16 is low as compared to XBB.1.5 and the other currently circulating variants, at this current time and with available eence”.
Here’s everything you need to know about the XBB.1.16 “Arcturus” variant.
What is XBB.1.16?
XBB.1.16, also dubbed “Arcturus”, is a sub-variant of COVID.
After the increase in cases, the WHO compared data from February and March 2023 in India and found that XBB.1.16 rose from 15% to 58%.
However, researchers concluded that infections from India did not report any differences in hospital cases and oxygen requirements for this strain compared to other variants.
Infectious disease epidemiologist Maria Van Kerkhove from the WHO has warned people to “be vigilant” and says the situation is being monitored.
“Growth advantage and immune escape are observed for XBB.1.16, including in countries where XBB.1.5 has become dominant recently.
“No changes in severity have been reported and it can cause a full range of disease. Be vigilant.”
Addressing the new variant’s emergence at a press conference on 29 March, Dr Van Kerkhove said: “This is the XBB.1.16. It’s actually very similar in profile to XBB.1.5.
“So, this is one to watch. It has been in circulation for a few months.”
How prevalent is it in the UK?
Professor Paul Hunter, an expert in researching transmission of emerging infectious diseases, tells Sky News XBB.1.16 “certainly has taken over in India but is not being as aggressive in the UK or the US”.
He continues: “It is increasing in the UK but not as rapidly as previous new variants did and is now responsible for about 2% of infections. It is increasing a bit faster in the US and already is at about 10% of reported infections.
“So it does look like it will become the dominant variant at some point, but whether it will generate a further wave in infections and, if so, how big that wave will be, is not yet clear,” he said.
How many cases are there in the UK?
In the UK – as of 17 April 2023 – there were 135 XBB.1.16 sequences in the UK, with 120 in England, eight in Wales, five in Scotland, and two in Northern Ireland.
Dr Meera Chand, deputy director at the UK Health Security Agency (UKHSA), said: “It is not unexpected to see new variants of SARS-CoV-2 emerge.
“UKHSA continues to analyse all available data relating to SARS-CoV-2 variants in the UK and abroad and is monitoring the situation closely.
“Vaccination remains our best defence against future COVID waves, so it is still as important as ever that people take up all the doses for which they are eligible as soon as possible.”
What is the level of risk?
As the first emergence of XBB.1.16 was more than three months ago, the WHO declared the level of risk regarding “growth advantage” as “moderate”.
The variant has not yet led to a global sweep as some previous variants have done.
“However, if the estimated growth rates are sustained, this variant may become the dominant variant in more countries and even globally over time,” it added.
Based on the severity and clinical considerations, the WHO said the level of risk remains “low”, after being monitored in India.
“Severity indicators have not increased across the Indian states, and neither are there any reports of severity in any of the other countries that have detected XBB.1.16,” the report said.
Professor Hunter says deaths associated with COVID-19 sub-variants may be difficult to read.
“I saw that it was reported that five deaths have been associated with this variant. But, it is difficult to read much into five deaths as at such small numbers random effects play a part.”
He adds: “As we are now only really diagnosing the more severely ill infections, it is likely that we will see apparent death rates per infection higher than is actually the case.
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Potential Arcturus symptoms
The symptoms of Arcturus appear to be the same as other current strains of COVID.
According to the Centers for Disease Control and Prevention (CDC) – the list includes mild and severe symptoms people with COVID could encounter, although the list does not include all the possible symptoms:
Fever Body chills Shortness of breath or difficulty breathing Fatigue Muscle or body aches Headache New loss of taste or smell Congestion or runny nose Nausea or vomiting Diarrhoea Pink eye
“The symptom that seems to be more common is ‘pink eye’ or conjunctivitis, especially in children,” Professor Hunter says.
In most cases, viral conjunctivitis can be mild and recover on its own without any medical treatment in around one or two weeks.
Should we be worried?
Professor Hunter says “indications from elsewhere are that it is no more lethal, but too early to be sure in the UK context.”
At present, he says, we “need to watch [for the sub-variant] but nothing so far to suggest a change in policy.”
What does Arcturus mean?
Dr Van Kerkhove from the WHO has said that no official nicknames are being used for sub-variants.
“We are not using nicknames for these subvariants, and I would kindly encourage you not to. Please,” she added.
But the name still seems to be making its way around social media.
Arcturus is the name of a giant red star in the northern hemisphere of the Earth and it is known to be one of the brightest stars in the constellation.
How do they determine a variant of interest (VOI)?
VOI is the emergence of strains that pose an increased risk to global public health, often with eence of transmission, but also with major uncertainties linked to it.
A variant under investigation (VUI) is when a strain is monitored closely and “mutations of the virus can be officially designated as under investigation,” says GOV UK.
For a variant of concern (VOC), there is usually clear eence of its severity and impact. This means there may be increased death rates and illnesses globally.
