WATCH: Experts stumped as new mystery illness affecting children could be linked to Covid-19
London - Nearly 100 children in the UK have suffered from a potentially deadly inflammatory syndrome linked to coronavirus.
Experts believe some children have a "delayed immune response" that leaves them severely ill for four or five days a month after being infected with the virus.
The condition, called pediatric multisystem inflammatory syndrome, has been reported in about 100 children in New York State, the New York Times reported.
Last month NHS England sent an alert to GPs about the syndrome, which causes sepsis-like symptoms and has killed a 14-year-old boy from London.
WATCH: What are the symptoms of pediatric multisystem inflammatory syndrome?
Russell Viner, president of the Royal College of Paediatrics and Child Health, said between 75 and 100 UK children have so far been treated for the syndrome.
"We can’t prove it is caused by Covid but it would be extremely odd if it was not linked to it," he added.
Some experts say the cases are likely to be the "tip of the iceberg" but Professor Viner emphasised that it is very rare.
Dr Liz Whittaker, of Imperial College London, said children affected by the new syndrome experience high fevers, severe abdominal pain and diarrhoea.
Some have a rash and red eyes and lips, and a small number develop shock and need intensive care. Those affected were aged between five and 15.
The symptoms are similar to Kawasaki disease, a rare illness that triggers inflammation in the walls of blood vessels and can lead to aneurysms and heart attacks.
Most of the children tested negative for coronavirus when they were admitted to hospital but antibody tests showed they had previously had the disease.
Dr Whittaker said: "The peak we’re seeing in children with this paediatric inflammatory syndrome is several weeks after the peak of Covid-19 across the country."
Professor Viner said the syndrome is "exceptionally rare" and should not prevent children going back to school.
A study in The Lancet on Wednesday revealed a small number of children in Italy and the US have also been affected by the disease.Daily Mail