Children over five at higher risk of COVID-related multisystem inflammatory syndrome

A study has found that older children and those with high blood markers for inflammation (ferritin) were at highest risk of severe multisystem inflammatory syndrome in children (MIS-C) and admission to intensive care.

The study, published in Canadian Medical Association Journal, included 232 children and teenagers under 18 admitted to one of 15 centres — 13 in Canada, one in Costa Rica and one in Iran — for suspected MIS-C between 1 March 2020 and 7 March 2021.

The patients met the World Health Organization’s definition for MIS-C, which includes fever persisting for at least three days, elevated C-reactive protein indicating inflammation, illness involving two or more systems with no obvious microbial cause of inflammation, and positivity for COVID-19 or suspected contact with a positive case.

Most patients – 89% – had gastrointestinal symptoms such as pain and dermatological problems like rashes and swelling. Cardiac involvement was found among 59%, while abnormalities in blood coagulation were present in 90%. Of the 232 children, 73 (31.5%) were admitted to ICU, and 47 (64%) of them needed treatment for very low blood pressure.

The risk of admission to the ICU was higher in children aged 6–12 years (44%) and 13–17 years (46%) than in children aged 0–5 years (18%). Children admitted to hospital later in the pandemic (between November 2020 and March 2021) were more likely to be admitted to the ICU (50 of 112, 45%) than those hospitalized earlier (23 of 120, 19%).

The authors noted challenges in diagnosing MIS-C. ‘Multisystem inflammatory syndrome in children is a new diagnosis, with differing diagnostic criteria that have not been validated,” wrote Dr Joan Robinson, a paediatrician at the University of Alberta.

‘Most of these children lacked a history of contact with a person with proven SARS-CoV-2 infection. Identifying exposure can be difficult as infected contacts may be asymptomatic or may never have been tested.’

The authors called for international consensus on MIS-C diagnostic criteria to enhance clinical care and research.

Photo by Olga Kononenko