Children with multisystem inflammatory syndrome (MIS-C), a rare condition linked with the virus that causes COVID-19, have biochemical indicators of cell injury and cell death that are distinct from other children with COVID, according to a new study.

The study, led by a team at the University of California, San Francisco, analysed 416 blood samples from 237 patients. They used high-speed, artificial intelligence-controlled molecular sequencing of blood-and-plasma RNA and plasma DNA.

The results, appearing in Cell Reports Medicine, showed that children with MIS-C have biomarkers indicating damage to multiple organs, the lining of blood vessels, and the nervous system.

MIS-C usually occurs two to six weeks after COVID-19 infection, resulting in inflammation of the heart, lungs, kidneys, brain, skin, eyes or gastrointestinal tract, according to the US National Institutes of Health.

The findings could lead to the development of tests that allow clinicians to distinguish between MIS-C and other conditions involving widespread inflammation, such as Kawasaki disease, septic shock, and severe COVID-19, and to the development of more appropriate treatments for each, the NIH noted.

A previous study of children and adolescents who received a COVID-19 vaccination following MIS-C found that there were no reports of serious complications, including myocarditis or MIS-C re-occurrence after the injection.

Everyone should stay up to date with COVID vaccines for their age group, as the US Centers for Disease Control and Prevention recommends, regardless of whether they have been infected with the virus.