Two U.S. research groups have reported finding nearly 300 cases of an alarming apparent side effect of Covid-19 in children, a condition called multisystem inflammation syndrome, or MIS-C. 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 studies, published in the New England Journal of Medicine, describe children who develop severe inflammation a few weeks after having had Covid-19. The inflammation often attacks multiple organ systems. In one of the studies, led by researchers at Boston Children’s Hospital, 80% of the children who developed the condition required intensive care, 20% required mechanical ventilation, and four children, or 2%, died. In the second study, from researchers from New York state, two children died.