At least five children — three in New York, and one each in France and Britain — have died from the syndrome, and at least two other deaths are suspect, AFP wrote.

Up to now, COVID-19 — with 4.5 million confirmed cases worldwide, and more than 300,000 deaths — has largely spared small children and teens, though many are thought to have been infected without showing symptoms.

But the new illness, while still very rare by comparison, suggested that no age bracket is safe.

Europe has seen some 230 suspected cases of the so-called pediatric inflammatory multisystem syndrome (PIMS) in children up to 14 years old, the European Center for Disease Prevention and Control (ECDC) said.

Doctors in Bergamo, northern Italy reported a 30-fold increase in the incidence of severe inflammatory disorders among young children, with ten cases from mid-February to mid-April as compared to 19 during the previous five years, according to a study this week in The Lancet.

In the US, where well over 100 cases have been identified in the New York area, health authorities have issued an alert for the mysterious illness.

“Initial reports hypothesis that this syndrome may be related to COVID-19,” World Health Organization chief Tedros Adhanom Ghebreyesus told a virtual briefing, calling on clinicians worldwide to help “better understand this syndrome in children.”

France’s state-run health watchdog described the likelihood of such a link as ‘very probable’.

Like Kawasaki disease, a rare condition that occurs in very young children, the new disorder can cause persistent fever, searing abdominal pain, rashes, and a swollen tongue.

Also compared to toxic shock syndrome, PIMS leads to inflamed blood vessels and, in some cases, damage to the heart.

A nine-year-old boy who died in the southern French city of Marseille was said to have suffered “a neurological injury related to cardiac arrest” — in other words, a heart attack.

A delayed impact

Experts speculate that the virus triggers a violent response in the immune system, causing it to turn against, rather than protect, the tissue and organs of affected children.

“They had the virus, the body fought it off earlier,” Sunil Sood, a pediatrician at Cohen Children’s Medical Center in New York, told AFP.

“But now there’s this delayed, exaggerated immune response.”

PIMS is different, however, from the Kawasaki syndrome in that it seems mainly to affect older children.