The latest Covid variant that has epidemiologists worried causes 'more fever' for those who catch it than most previous strains.
New Covid-19 variant Arcturus is rapidly spreading across the globe and worried health officials have warned it has new symptoms not seen in previous strains.
Infectious disease doctors say the strain's mutation makes it highly transmissible.
Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee, said: "It tends to produce more fever than some of the other strains we've seen.
Arcturus is a subvariant of Omicron which seems to be more transmissible, having fuelled a recent surge of Covid cases in India, years on from the height of the pandemic.
Dr Schaffner continued: "But the most distinctive feature is that it seems to have a tendency to produce conjunctivitis, particularly in children."
Despite sometimes causing a worse fever, the strain doesn't cause more severe cases.
Existing vaccines that work on Omicron also appear to work well against Acturus.
Cases of Arcturus, which is also known as XBB.1.16, are rising across the world.
The variant has been found in the US - as well as the United Kingdom among 29 countries in total - and while levels have so far remained low, health officials are keeping a close eye on it.
This latest variant reportedly also comes with a new symptom, not seen before with a coronavirus strain.
Reports from doctors in India, where the strain is rife, have said they are seeing more children and adolescents with the variant presenting with conjunctivitis - or pink eye.
Indian paediatrician Vipn M. Vashishtha, also a member of the WHO's Vaccine Safety Net programme, said at the start of April that he had seen paediatric Covid cases "once again after a gap" of six months.
He explained youngsters were presenting with a high fever, cold and cough, and "itchy conjunctivitis" with "sticky eyes".
However, Dr Michael Chang, a paediatric infections diseases expert at UTHealth Houston and Children's Memorial Hermann Hospital, told Yagoo News there isn't enough evidence to prove the new Covid variant is causing conjunctivitis.
"We don't have the context of whether they're seeing that in some of the regions in India," he said.
"We know their Covid cases are going up, and presumably, these kids are testing positive for Covid, but we don't know if they're testing positive for anything else either."
He explained there are other viruses which can cause pink eye - including adenovirus which is common in spring and summer.
"We are seeing adenovirus circulating," he said, "so even if Covid cases go up, unless you're doing testing for both Covid and adenovirus, which most people aren't... it may be difficult [to determine] what's causing your pink eye."
Arcturus, known as XBB.1.16, was mentioned by the World Health Organisation (WHO) in March as a "variant of monitoring" - a lesser threat than a "variant of interest".
But, the status of the variant could be changed if there are signs of increase transmission or severity, or if it appears to be able to evade antibodies.
Arcturus has been found in at least 29 countries, including the US, and seems to be spreading across the globe quickly.
