Alberta Health is investigating three probable MIS-C (multisystem inflammatory syndrome in children) cases that could be related to COVID-19. While researchers have previously reported on the condition, the papers mark the first attempt to measure how frequently the side effect occurs and how it affects children who develop it. The inflammation often attacks multiple organ systems.
The second study, which observed patients in NY and was conducted by the state's health department, found another 95 confirmed cases, with 4 out of 5 needing admission to intensive care unit and two patients dying.
The papers, published online Monday in the New England Journal of Medicine, provide the fullest report yet on the condition.
Cardiac involvement was common in both studies: In the national data, 80% had cardiovascular involvement, 48% received vasoactive support, and 8% of the children had coronary artery aneurysms documented with z scores ≥2.5.
At least 35 states have had cases, and they seem to crop up a few weeks after local COVID-19 activity peaks, said Dr. Adrienne Randolph of Boston Children's Hospital. Some children may have symptoms resembling Kawasaki disease, a rare condition in children that can cause swelling and heart problems.
"Overall, a consistent clinical picture is emerging", said Michael Levin, PhD, of Imperial College London, in an accompanying editorial.
"While they are confirmed from our current definition, that definition does not now require a diagnosis of COVID-19 because we want to make sure we don't miss any cases in this early information-gathering phase". Children are much more likely than adults to be symptom-free or have only mild symptoms when they contract Covid-19.
"There is concern that children meeting current diagnostic criteria for MIS-C are the 'tip of the iceberg, ' and a bigger problem may be lurking below the waterline", Levin wrote. The infection rate in people under the age of 21 years was 322 in 100,000 over the course of the period studied.
At least 285 US children have developed a serious inflammatory condition linked to the coronavirus and while most recovered, the potential for long-term or permanent damage is unknown, two new studies suggest.
This is a breaking news story and will be updated.