The UK health minister said Tuesday he was "very concerned" about signs of coronavirus-related syndrome in children, but stressed that more research was needed and remained very rare.
The state's National Health Service (NHS) warned over the weekend of a small number of children who showed unusual symptoms, including abdominal pain and inflammation of the heart.
According to a report in the Health Service Journal, they had to be admitted to the intensive care unit.
"I am very concerned about the first signs that an autoimmune reaction in children that causes a major illness occurs in rare cases," Health Minister Matt Hancock told LBC Radio.
He added: "It is a new disease that we believe is caused by the coronavirus and the COVID-19 virus."
But Hancock said that some of the children who have this new disease tested positive for the virus, while others didn't.
"We are doing a lot of research now. I would also like to emphasize that it is rare. Although it is very important for the children who get it, the number of cases is small," he said.
The Guardian newspaper reported that there were at least 12 cases.
According to the Pediatric Intensive Care Society, the NHS alarm warned of common overlapping features of Toxic Shock Syndrome (TSS) and atypical Kawasaki disease, as well as blood parameters related to severe COVID-19.
TSS is a serious illness associated with infections, while Kawasaki causes inflammation of the blood vessels and mainly occurs in children under five years of age.
NHS England national medical director Stephen Powis said Monday it was "too early to say" whether the new disease was linked to the coronavirus, but the issue is under investigation.
English chief physician Chris Whitty said it was "totally plausible" that it was related to COVID-19.
Children have died of coronavirus, but serious complications are rare.
"Evidence from around the world shows that children appear to be the least affected part of the population," said Russell Viner, president of the Royal College of Pediatrics and Child Health.
But he added, "New diseases can come in a way that surprises us, and doctors need to be alerted to emerging signs of certain symptoms or underlying conditions that could make a patient more susceptible to the virus."
(Except for the headline, this story was not edited by NDTV staff and published from a syndicated feed.)