Risk factors for severe COVID-19 in hospitalized children in Canada: A national prospective study from March 2020--May 2021 (preprint)

ABSTRACT

Background: Children living with chronic comorbid conditions are at increased risk for severe COVID-19, though there is limited evidence regarding the risks associated with specific conditions and which children may benefit from targeted COVID-19 therapies. The objective of this study was to identify factors associated with severe disease among hospitalized children with COVID-19 in Canada. Methods: We conducted a national prospective study on hospitalized children with microbiologically confirmed SARS-CoV-2 infection via the Canadian Paediatric Surveillance Program from April 2020--May 2021. Cases were reported voluntarily by a network of >2800 paediatricians. Hospitalizations were classified as COVID-19-related, incidental infection, or infection control/social admissions. Severe disease (among COVID-19-related hospitalizations only) was defined as disease requiring intensive care, ventilatory or hemodynamic support, select organ system complications, or death. Risk factors for severe disease were identified using multivariable Poisson regression, adjusting for age, sex, concomitant infections, and timing of hospitalization. Findings: We identified 544 children hospitalized with SARS-CoV-2 infection, including 60{middle dot}7% with COVID-19-related disease and 39{middle dot}3% with incidental infection or infection control/social admissions. Among COVID-19-related hospitalizations (n=330), the median age was 1{middle dot}9 years (IQR 0{middle dot}1--13{middle dot}3) and 43{middle dot}0% had chronic comorbid conditions. Severe disease occurred in 29{middle dot}7% of COVID-19-related hospitalizations (n=98/330), most frequently among children aged 2-4 years (48{middle dot}7%) and 12-17 years (41{middle dot}3%). Comorbid conditions associated with severe disease included technology dependence (adjusted risk ratio [aRR] 2{middle dot}01, 95% confidence interval [CI] 1{middle dot}37-2{middle dot}95), neurologic conditions (e.g. epilepsy and select chromosomal/genetic conditions) (aRR 1{middle dot}84, 95% CI 1{middle dot}32-2{middle dot}57), and pulmonary conditions (e.g. bronchopulmonary dysplasia and uncontrolled asthma) (aRR 1{middle dot}63, 95% CI 1{middle dot}12-2{middle dot}39). Interpretation: While severe outcomes were detected at all ages and among patients with and without comorbidities, neurologic and pulmonary conditions as well as technology dependence were associated with increased risk of severe COVID-19. These findings may help guide vaccination programs and prioritize targeted COVID-19 therapies for children. Funding: Financial support for the CPSP was received from the Public Health Agency of Canada.