Researchers in the United States have said they have seen the development of rare inflammatory problems like stomach pain, bubbles and swelling in the arteries of children who have been exposed to the novel coronavirus infection.
Paediatric specialists, including representatives from the Centers for Disease Control (CDC) and Prevention and the National Institutes of Health, opined that the cases appeared to have some characteristics of an illness known as Kawasaki disease, The Washington Post reported.
The doctors, during a call on Zoom app, noted that the mysterious symptoms started three to four weeks after the big wave of COVID-19 hit Europe and the US. At present, hospitals worldwide have identified about 100 similar cases of the syndrome, while half of them are in the US.
"Not in my lifetime have I seen anything remotely similar to what is going on right now," said Jane Newburger, medical director of the cardiac neurodevelopment programme at Boston Children's Hospital.
But the number of affected children is still tiny, much lower than the number of the seriously ill from the flu in the same community, the researchers further said.
"There is this very small number of patients, thankfully, who are presenting with this shock syndrome, at the same time that there are a large number of (COVID-19) patients in the same community," said Jane Burns, a professor of paediatrics at the University of California at San Diego School of Medicine.
Burns, along with other doctors, emphasised that parents should not pc as the vast majority of those younger than 18 who are infected with coronavirus have mild symptoms or none at all.
However, researchers have not confirmed so far whether the condition of the mysterious syndrome is caused by COVID-19 or something else.
"Those with 'paediatric multi-system inflammatory syndrome,' as doctors call the new illness, are a small genetic subset of children who appear to be susceptible to this crazy thing," Burns said.
On Monday, New York City issued a bulletin warning doctors they had found 15 children with the condition at their hospitals, and the CDC is contacting health departments about surveillance measures.
On late Wednesday, the American Heart Association issued its own alert saying that some children "are becoming very ill extremely quickly," so those with symptoms should be swiftly evaluated.
For more typical respiratory viruses such as influenza, children are often the first to become sick. While COVID-19 is an anomaly, killing the elderly at high rates while leaving the very young mostly untouched. Only a small fraction of American children -- including an infant and a five-year-old who were children of first responders -- have died of the disease.
Separately, the CDC is financing the creation of a registry that will track COVID-19 cases among children at more than 35 US children's hospitals to understand why some children get very ill while most do not.
"We know the rate of infection in children is way lower than in adults," said Alkis Togias of the National Institute of Allergy and Infectious Diseases.
"What we do not know is whether, actually, they do carry the virus and transmit it without getting sick or getting very mild symptoms. We have so little knowledge, I cannot give you an answer on almost anything related to children. So we need to figure this out," Togias added.
( With inputs from ANI )