Resource use and disease severity of children hospitalized for COVID-19 versus multisystem inflammatory syndrome in children (MIS-C) in Canada.

Background: Direct comparisons of paediatric hospitalizations for acute coronavirus disease 2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C) can inform health system planning. We describe the absolute and relative hospital burden of acute paediatric COVID-19 and MIS-C in Canada.
Methods: This national prospective study was conducted via the Canadian Paediatric Surveillance Program from March 2020-May 2021. Children younger than 18 years old and hospitalized for acute COVID-19 or MIS-C were included in the analysis. Outcomes included supplemental oxygen (low-flow oxygen or high-flow nasal cannula), ventilation (non-invasive or conventional mechanical), vasopressors, paediatric intensive care unit (PICU) admission, or death. Adjusted risk differences (aRD) and 95% confidence intervals (CI) were calculated to identify factors associated with each diagnosis.
Results: Overall, we identified 330 children hospitalized for acute COVID-19 (including five deaths) and 208 hospitalized for MIS-C (including zero deaths); PICU admission was required for 49.5% of MIS-C hospitalizations versus 18.2% of acute COVID-19 hospitalizations (aRD 20.3; 95% CI, 9.9-30.8). Resource use differed by age, with children younger than one year hospitalized more often for acute COVID-19 (aRD 43.4% versus MIS-C; 95% CI, 37.7-49.1) and more children 5-11 years hospitalized for MIS-C (aRD 38.9% vs. acute COVID-19; 95% CI, 31.0-46.9).
Conclusion: While there were more hospitalizations and deaths from acute paediatric COVID-19, MIS-C cases were more severe, requiring more intensive care and vasopressor support. Our findings suggest that both acute COVID-19 and MIS-C should be considered when assessing the overall burden of severe acute respiratory syndrome coronavirus 2 in hospitalized children.
Competing Interests: Competing interests CMH is the Director of Children’s Mental Health of Ontario, and the Director of Medical Affairs for the Canadian Paediatric Society and Canadian Paediatric Surveillance Program. MPM has received consulting fees from Sobin and Abbvie and payment for expert testimony from the Canadian Medical Protective Association. RAB has received honoraria and participated in advisory boards with SOBI, Roche, Amgen, and AbbVie. KB served as Past President of the Community Paediatrics Section of the Canadian Paediatric Society and has received royalties from Brush Education. TLB is an employee of the Public Health Agency of Canada (PHAC). KC is Chair of the Acute Care Committee of the Canadian Paediatric Society and is past-president of the Emergency Medicine Section of the Canadian Paediatric Society. EJD is Chair of the Scientific Research Committee and a director of Epilepsy Canada. She is also a member of Partners Against Mortality in Epilepsy and the advisory boards of Cardiol, Pendopharm and Stoke Therapeutics. CF is Chair of the Scientific Steering Committee for the Canadian Paediatric Surveillance Program, former Chair of the Specialty Committee in Paediatrics of the Royal College of Physicians and Surgeons of Canada, former president of the Canadian Paediatric Society, and member of the Executive as Secretary of the Canadian Critical Care Society. She has received reimbursement for travel expenses from Canadian Paediatric Society and the Royal College of Physicians and Surgeons of Canada. She has also received an honorarium for a presentation at a continuing education conference from the Université de Sherbrooke. SF is the President of the Association of Medical Microbiology and Infectious Disease Canada and has received consulting fees from Toronto Metropolitan University. RML has received honoraria for serving as a consultant to Sobi, Novartis, Sanofi, and Eli Lilly, as chair for data monitoring committees for Eli Lilly and Novartis, and from the Canadian Rheumatology Association. JP has received consultant fees from AbbVie, honoraria from AbbVie, AstraZeneca and Seegene, and he received respiratory virus testing materials from Seegene for his institution. He has participated in ad hoc advisory board meetings for AbbVie and Merck and is a voting member of the National Advisory Committee on Immunization. RP is a consultant for Verity Pharmaceuticals. MS is supported via salary awards from the BC Children’s Hospital Foundation and the Michael Smith Foundation for Health Research and has been an investigator on projects funded by GlaxoSmithKline, Merck, Moderna, Pfizer, Sanofi-Pasteur, Seqirus, Symvivo and VBI Vaccines. All funds have been paid to his institute, and he has not received any personal payments. MIS is an employee of the Public Health Agency of Canada. EH has participated in advisory board meetings of CSL-Behring and Takeda, data safety monitoring boards of Rocket Pharmaceutical and Jasper Therapeutics, and has patent applications with Immugenia and Immune Biosolutions. RS has received honoraria and served on an advisory board and as a consultant with Novartis, honoraria from Canadian Rheumatology Association, is a board member for Rheumatology for All, and her institution receives funding from Bristol Myers Squibb for a patient registry for which she is Principal Investigator. RSMY has received grant funding from CFI, CIHR, Genome Canada, PHAC and the COVID-19 Immunity Task Force, and The Arthritis Society; is a member of the Science and Industry Advisory Committee at Genome Canada and Medical Advisory Board at Kawasaki Disease Canada; and a member of a data safety monitoring board for a study on IL-1 inhibitors for Kawasaki Disease. FK has received honoraria for presentations given to the Association des Pédiatres du Québec and receives CMV testing kits from Altona Diagnostics. SKM has received honoraria for lectures from GlaxoSmithKline, was a member of ad hoc advisory boards for Pfizer Canada and Sanofi Pasteur, and is an investigator on an investigator led grant from Pfizer. DSF, OD, TET, MK, and MLT have no conflicts of interest to report.