A mysterious condition that could be linked to COVID-19 has been reported in hundreds of children in several European countries and North America.
The World Health Organization (WHO) put out a scientific brief this past month describing "clusters of children and adolescents requiring admission to intensive care units with a multisystem inflammatory condition with some features similar to those of Kawasaki disease and toxic shock syndrome."
England's health service had alerted at the end of April that cases of children in intensive care with "a multi-system inflammatory state" were rising.
Children were displaying overlapping symptoms of severe COVID-19, toxic shock syndrome and Kawasaki disease.
The new ailment is being called multisystem inflammatory syndrome in children or MIS-C.
The UK, France, Italy, Spain, and the US have all reported cases with some children testing positive for COVID-19 or coronavirus antibodies, meaning they were previously exposed to the virus.
A nine-year-old in France recently died due to complications from cardiac arrest related to the syndrome. The child had tested positive for coronavirus antibodies.
At least three children have died in New York from this "new emerging syndrome".
What are the symptoms to look out for?
The WHO says to look out for fever, inflammation, hypotension, and shock.
New York City's department of health warned to look for signs of fever, prolonged abdominal pain, skin rash, bloodshot eyes, racing heart among other symptoms.
The UK’s Royal College of Paediatrics and Child Health said symptoms often include a persistent fever over 38.5°C and can include abdominal pain, confusion, conjunctivitis, diarrhoea, swelling, sore throat, rash or vomiting.
The symptoms reported often fulfil criteria for classic Kawasaki Disease, which can cause blood vessels to become inflamed and swollen and lead to complications such as the swelling of the arteries.
“The characteristics of [Kawasaki Disease] are fever, red eyes, red lips, red tongue, a rash, there can be swelling and redness of the hands and feet and there can also be swelling of the lymph nodes and neck,” Adriana Treboulet, associate director of the Kawasaki Disease Research Centre at the University of California, San Diego, told Euronews in April.
“[Kawasaki Disease] can cause swelling of the arteries of the heart and that can be lifelong and it can lead to things such as a heart attack,” Treboulet added.
What is the link between this new syndrome and COVID-19?
In countries with large outbreaks of coronavirus, there have been more reported cases of paediatric shock and Kawasaki disease-like symptoms. Some of these children have tested positive for COVID-19 or coronavirus antibodies.
France’s public health agency said they have had reports of at least 144 children between the ages of five and 20 with atypical paediatric diseases since March 1.
"Initial hypotheses are that this syndrome may be related to COVID-19 based on initial laboratory testing," the WHO said on May 15.
"It is essential to characterise this syndrome and its risk factors, to understand causality, and describe treatment interventions."
Professor Robert Tulloh, a cardiologist at Bristol Royal Hospital for Children, told Euronews that doctors are “aware that COVID-19 infection has an effect on T cells and appears to reduce their ability to limit the inflammatory process.”
Severe COVID-19 in adults can lead to “a marked inflammatory response which makes people really sick… [whereas] in children, it seems that the initial infection is usually very mild.”
“Most [children] do not seem to go on get the pneumonia and recover quickly. However, some develop a similar inflammatory response that the adults do.”
A few go on to develop giant coronary artery aneurysms or swelling of the heart vessels.
Should we be concerned?
"[Children] tend to have overwhelming mild disease," said Dr Maria Van Kerkhove, COVID-19 technical lead at WHO's health emergencies programme said in April
"But there are some children who have developed severe disease and some children who have died.
Professor Russell Viner, President of the Royal College of Paediatrics and Child Health, stressed in April that instances of children falling severely ill with COVID-19 have been "very rare".
"Evidence from throughout the world shows us that children appear to be part of the population least affected by this infection.”
“It is worth remembering that the numbers of children affected are still very small,” said Tulloh.
“There appear to be around 250 in Europe in total - for a population of many millions. Hence we are keen to reassure parents that it is uncommon and they should not worry unduly.”
Nonetheless there is an urgent effort underway to learn more about this syndrome and how children are impacted by COVID-19.