Scientists say a blood test could identify children most at-risk for a rare inflammatory syndrome in reaction to the coronavirus

• UK doctors collected blood from children sick with multisystem inflammatory syndrome and discovered that their blood had high concentrations of certain compounds.
• A routine blood test could reveal the existence of these compounds, and could let doctors know if the children were at risk for the disease.
• A European trial is currently collecting blood samples to see how the presence of these compounds affects children.
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Scientists say they have developed a blood test that could identify which children are most at risk of the mysterious new syndrome that has been sending hundreds of children around the world to hospital ICUs.

This multisystem inflammatory syndrome, which has symptoms similar to Kawasaki's disease, comes with symptoms of fever, skin rashes, and abdominal pain, may be a result of children's developing immune systems overreacting to the virus.

Imperial College London researchers took blood from the sickest children and found that they had high concentrations of certain blood components that could be easily detected. These compounds, like ferritin and C-reactive protein, are markers of inflammation. This group of blood compounds, whose presence is easily detectable by routine lab tests, may reveal which children are most at risk.

"We know that these markers are present in the very sick patients and at lower levels in some patients with normal Kawasaki disease," Michael Levin, a professor at Imperial, told The Guardian. "We think they can help us decide which children are at risk of progressing to cardiac failure."

A trial known as Diamonds, short for Diagnosis and Management of Febrile Illness using RNA Personalised Molecular Signature Diagnosis, is collecting blood samples to try and discover more about these compounds.

The new syndrome seems to predominantly affect children

Doctors still do not fully understand why this new syndrome is occurring, or why it seem to mostly affect children.

The new syndrome has symptoms similar to the rare Kawasaki disease, with doctors recording symptoms like swelling of hands and feet, swollen lymph glands in the neck and inflammation of the mouth and lips.

Kawasaki disease causes inflammation in the walls of the arteries throughout the body, and about one in 10,000 children under the age of 5 get the disease annually.

A study in The Lancet found a "strong association" between COVID-19 and the syndrome. The study authors estimated that only one in 1,000 children exposed to the coronavirus will have this reaction.

Kawasaki disease can normally be treated with high doses of aspirin or an IV drip of gamma globulin. But according to the US National Library of Medicine, without treatment, 15 to 25% of people with disease will develop thinning or bulging of the walls of the arteries that supply blood to the heart, which can be fatal.

Public health organizations have been sounding the alarms on the new syndrome. The CDC quickly published a health advisory warning doctors to look out for new cases, and the World Health Organization has put its clinical network on high alert for signs of the disease in children.