PARIS Europe and the United States have seen sharp surges in recent weeks of a severe immune disorder in children that is linked to Covid-19, the health authorities have reported, sounding an alarm.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 suspected."Initial reports hypothesise that this syndrome may be related to Covid-19," World Health Organisation (WHO) chief Tedros Adhanom Ghebreyesus told a virtual briefing on Friday, 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".Up to now, Covid-19 - with more than 4.6 million cases worldwide, and more than 309,000 deaths - has largely spared small children and teens, though many are thought to have been infected without showing symptoms.But the new illness, while is still very rare by comparison, suggests that no age bracket is safe.Europe has seen some 230 suspected cases of so-called paediatric inflammatory multi-system syndrome (Pims) in children up to 14 years old, the European Centre for Disease Prevention and Control said on Friday. In the US, where well over 100 cases have been identified in the New York area, the health authorities have issued an alert for the mysterious illness.The WHO issued a preliminary definition of the syndrome, which it said had become more frequent during the current pandemic but has also appeared in children who did not test positive for Covid-19.The condition affected children and adolescents showing fever for more than three days, with elevated markers of inflammation.The children also showed at least two of the following symptoms: rash or signs of inflammation around the mouth, hands or feet; shock or low blood pressure; heart problems; evidence of bleeding disorder; and acute gastrointestinal problems.The case definition pertained to children who had contracted Covid-19 or had likely contact with Covid-19 patients, and had no other obvious microbial cause of inflammation, it said."We know so far very little about this inflammatory syndrome," said WHO epidemiologist Maria Van Kerkhove.Experts speculated 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.Pims is different from the Kawasaki syndrome in that it seems to affect mainly older children. "The population we are seeing are seven or eight (years old) through to 17," Dr Karyn Moshal, a paediatric infectious disease consultant at Great Ormond Street Hospital in London told The BMJ, a medical journal."Initial reports hypothesise that this syndrome may be related to Covid-19," World Health Organisation chief Tedros Adhanom Ghebreyesus told a virtual briefing on Friday, calling on clinicians worldwide to help "better understand this syndrome in children".Researchers are groping for answers as to why some children and not others get hit with the syndrome. In adults, the strongest predictors have been pre-existing health problems, especially high blood pressure, but none of these apply to young children.One theory emerging from the recent cases points to a genetic link. In England, six of the first eight cases observed were in children of Afro-Caribbean origin, according to a study last week in The Lancet. The boy who died in France was also of African origin.At its briefing, the WHO urged governments and companies to work together to develop a vaccine and treatments for Covid-19, and make distribution equitable."Traditional market models will not deliver at the scale needed to cover the entire globe," said Dr Tedros.AGENCE FRANCE-PRESSE, REUTERS