Comparison of Symptoms Associated With SARS-CoV-2 Variants Among Children in Canada
Authors: Sumner Madeleine W. , Xie Jianling , Zemek Roger , Winston Kathleen , Freire Gabrielle , Burstein Brett , Kam April , Emsley Jason , Gravel Jocelyn , Porter Robert , Sabhaney Vikram , Mater Ahmed , Salvadori Marina I. , Berthelot Simon , Beer Darcy , Poonai Naveen , Moffatt Anne , Wright Bruce , Freedman Stephen B. ,   Pediatric Emergency Research Canada (PERC) COVID Study Group, Ali Samina , Newton Mandi , Alqurashi Waleed , Lorenzo Melissa , Crawford Tyrus , Emerton Becky 
Published: March 2023

ImportanceClinical manifestations of SARS-CoV-2 variants have not been systematically compared in children.ObjectiveTo compare symptoms, emergency department (ED) chest radiography, treatments, and outcomes among children with different SARS-CoV-2 variants.Design, Setting, and ParticipantsThis multicenter cohort study was performed at 14 Canadian pediatric EDs. Participants included children and adolescents younger than 18 years (hereinafter referred to as children) tested for SARS-CoV-2 infection in an ED between August 4, 2020, and February 22, 2022, with 14 days of follow-up.Exposure(s)SARS-CoV-2 variants detected on a specimen collected from the nasopharynx, nares, or throat.Main Outcomes and MeasuresThe primary outcome was presence and number of presenting symptoms. The secondary outcomes were presence of core COVID-19 symptoms, chest radiography findings, treatments, and 14-day outcomes.ResultsAmong 7272 participants presenting to an ED, 1440 (19.8%) had test results positive for SARS-CoV-2 infection. Of these, 801 (55.6%) were boys, with a median age of 2.0 (IQR, 0.6-7.0) years. Children with the Alpha variant reported the fewest core COVID-19 symptoms (195 of 237 [82.3%]), which were most often reported by participants with Omicron variant infection (434 of 468 [92.7%]; difference, 10.5% [95% CI, 5.1%-15.9%]). In a multivariable model with the original type as the referent, the Omicron and Delta variants were associated with fever (odds ratios [ORs], 2.00 [95% CI, 1.43-2.80] and 1.93 [95% CI, 1.33-2.78], respectively) and cough (ORs, 1.42 [95% CI, 1.06-1.91] and 1.57 [95% CI, 1.13-2.17], respectively). Upper respiratory tract symptoms were associated with Delta infection (OR, 1.96 [95% CI, 1.38-2.79]); lower respiratory tract and systemic symptoms were associated with Omicron variant infection (ORs, 1.42 [95% CI, 1.04-1.92] and 1.77 [95% CI, 1.24-2.52], respectively). Children with Omicron infection most often had chest radiography performed and received treatments; compared with those who had Delta infection, they were more likely to have chest radiography performed (difference, 9.7% [95% CI, 4.7%-14.8%]), to receive intravenous fluids (difference, 5.6% [95% CI, 1.0%-10.2%]) and corticosteroids (difference, 7.9% [95% CI, 3.2%-12.7%]), and to have an ED revisit (difference, 8.8% [95% CI, 3.5%-14.1%]). The proportions of children admitted to the hospital and intensive care unit did not differ between variants.Conclusions and RelevanceThe findings of this cohort study of SARS-CoV-2 variants suggest that the Omicron and Delta variants were more strongly associated with fever and cough than the original-type virus and the Alpha variant. Children with Omicron variant infection were more likely to report lower respiratory tract symptoms and systemic manifestations, undergo chest radiography, and receive interventions. No differences were found in undesirable outcomes (ie, hospitalization, intensive care unit admission) across variants.