COVID-19 surge: What you need to know about 'Arcturus' subvariant that has this new symptom

A new coronavirus subvariant under the World Health Organization's (WHO) radar is causing a new symptom in children which is starkly different from the parent Omicron spread. The Omicron subvariant XBB.1.16, also known as Arcturus, is causing a rise in COVID-19 cases in India. Cases linked to this variant are also rising in Singapore, the US, and Australia among others. 

The XBB.1.16 subvariant is a combination of two subvariants of the Omicron variant. A University of Tokyo preprint study also suggested the subvariant spreads around 1.17 to 1.27 times more efficiently than the XBB.1 and XBB.1.5 or Kraken subvariants. "We first show that XBB.1.16 had an effective reproductive number (Re) that was 1.27- and 1.17-fold higher than the parental XBB.1 and XBB.1.5, respectively, suggesting that XBB.1.16 will spread worldwide in the near future," the preprint study read. 

The name Arcturus has been popularised by the former Indian Academy of Paediatrics Committee on Immunisation convenor Vipin M Vashishtha. He used it as a hashtag in a tweet in March to warn about the new COVID-19 cases. 

He said in a tweet, “All eyes should be on India! If XBB.1.16 aka Arcturus could succeed to wade through the ‘sturdy’ population immunity of Indians that successfully resisted the onslaught of variants like BA.285, BA.5, BQs, XBB.1.5, then the whole world must be seriously worried!”

He further noted that the XBB.1.16 variant is capable of shutting off innate as well as adaptive responses. Vashishtha wrote, “I would be surprised if it could generate a major surge here. All will depend on how well population immunity would resist this against the backdrop of differentially imprinted immunity and its waning over time!"

Arcturus COVID-19 subvariant symptoms

Dr Vashishtha said that a few symptoms in children are high fever, cough, “itchy” conjunctivitis or pink eye without pus but with sticky eyes. He added that this is something he never saw in the earlier COVID-19 waves. 

Pediatrician Dr Rahul Nagpal told India Today that doctors have seen rising COVID-19 cases in children with conjunctivitis. He added, “Usually, these children come with simple respiratory infections of cough, cold, and fever, and when tested they turn out to be positive.”

He further said the main symptoms of XBB.1.16 in adults resembled the flu including nasal discharge, sore throat, and cough. 

Nebraska Medicine’s Truhlsen Eye Institute said in a blog post that the virus has been found in the eye’s tear film, the thin layer of fluid covering the eye’s outer surface. The virus in the eye’s tear film can lead to conjunctivitis. 

Latest on XBB.1.16 coronavirus subvariant 

WHO’s COVID technical lead Maria Van Kerkhove said XBB.1.16 is considered “one to watch”. It also declared the XBB.1.16 as a subvariant “under monitoring” in late March and said that it is the most transmissible subvariant yet. 

She added, “We haven’t seen a change in severity in individuals or in populations but that’s why we have these systems in place, systems to track the variants, global collaborations to assess transmissibility, immune escape, severity, and the impact of any of our interventions including diagnostics, therapeutics, and vaccines.”

COVID-19 cases, deaths in India

India has reported 10,158 new infections in the last 24 hours and the COVID-19 positivity rate surged past the 4 per cent mark. While the daily positivity rate stood at 4.42 per cent, the weekly positivity rate stood at 4.02 per cent. The country has a total of 44,998 active cases as of Thursday, news agency ANI reported. More than 7,800 new cases were reported on Wednesday. 

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