42 Clinical features and severity of COVID-19 with respiratory virus coinfections versus SARS-CoV-2 monoinfection in hospitalized children: A Canadian national surveillance study
Authors: Chiara Costanza Di , Farrar Daniel S , Bettinger Julie A , Campigotto Aaron , Deeks Shelley , Drouin Olivier , Embree Joanne , Halperin Scott A , Jadavji Taj , Kazmi Kescha , Hepburn Charlotte Moore , Papenburg Jesse , Purewal Rupeena , Sadarangani Manish , Sauvé Laura , Top Karina A , Kakkar Fatima , Morris Shaun K 
Published: October 2024

Abstract

Background
The co-circulation of SARS-CoV-2 alongside other respiratory viruses has led to the risk of coinfections, potentially intensifying the severity of cases, especially in children.

Objectives
This study examined the epidemiology, clinical characteristics, and outcomes of SARS-CoV-2 respiratory virus coinfections in comparison to SARS-CoV-2 monoinfections in hospitalized children.

Design/Methods
A nationwide surveillance study was conducted to assess paediatric COVID-19-related hospitalizations across Canada from April 2020 to May 2022. Data were captured through two datasets covering ~90% of all Canadian tertiary-care paediatric beds: The Canadian Paediatric Surveillance Program and the Canadian Immunization Monitoring Program, ACTive. Coinfections were defined as the simultaneous detection of SARS-CoV-2 and ≥1 other respiratory virus. Severe infection was defined as intensive care, ventilatory, or hemodynamic support needs, organ systems complications, or death. Variables and outcomes were summarized and compared, and risk ratios were computed using Poisson regression, adjusting for age, gender, comorbid conditions, SARS-CoV-2 lineage, and vaccination status.

Results
Out of 1501 COVID-19-related hospitalizations, 163 (10.9%) had documented coinfections with 44/163 [27%] involving SARS-COV-2 plus ≥2 other respiratory viruses. The majority of SARS-CoV-2 monoinfections (1176/1501, 87.9%) and coinfections (139/163, 85.3%) belonged to the Omicron era (Figure A). RSV (66/163, 40.5%) and Enterovirus/rhinovirus (61/163, 37.4%) coinfections were the most common. Coinfection cases were significantly younger than monoinfection cases (median age 1.2 [IQR:0.3-3.3] vs 1.6 [IQR:0.3-7.0] years, p=0.04). Overall, severe disease was more common among cases with any coinfection (38.0%) than SARS-CoV-2 monoinfection (25.7%; adjusted risk ratio 1.45, 95% confidence interval 1.17-1.80) (Figure B). In particular, we observed that severe outcomes were significantly higher in SARS-CoV-2 coinfections compared to monoinfections during the Omicron era (Figure C-D). Overall, 26/61 (42.6%) Enterovirus/Rhinovirus and 20/66 (30.3%) RSV coinfections were associated with severe outcomes.

Conclusion
Children with documented coinfections had more severe respiratory disease compared to SARS-COV-2 monoinfections. However, children with severe COVID-19 may have been more likely tested for multiple viruses, leading to a risk of underestimation of coinfections among children with milder disease. Further work is needed to assess how different virus coinfections may affect children and which, if any, may be a predominant driver of disease severity.
1Severe disease was defined as intensive care, ventilatory, or hemodynamic support requirements, organ system complications, or death. 2Lineage was first assigned based on available genetic sequencing data. If missing, lineage was imputed based on the dominant circulating lineage at the provincial level according to the GISAID database.