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.

ObjectiveTo estimate the proportion of SARS-CoV-2 infected children experiencing hospitalization, intensive care unit (ICU) admission, severe outcomes, and death.Data SourcesPubMed, Embase, and MedRxiv were searched for studies published between December 1, 2019 and May 28, 2021. References of relevant systematic reviews were also screened.Study SelectionWe included cohort or cross-sectional studies reporting on at least one outcome measure (i.e., hospitalization, ICU admission, severe outcomes, death) for ≥100 children ≤21 years old within 28 days of SARS-CoV-2 positivity; no language restrictions were applied.Data Extraction and SynthesisTwo independent reviewers performed data extraction and risk of bias assessment. Estimates were pooled using random effects models. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.Main Outcomes and MeasuresPercentage of SARS-CoV-2 positive children experiencing hospitalization, ICU admission, severe outcome, and death.Results118 studies representing 3,324,851 SARS-CoV-2 infected children from 68 countries were included. Community-based studies (N = 48) reported that 3.3% (95%CI: 2.7–4.0%) of children were hospitalized, 0.3% (95%CI: 0.2–0.6%) were admitted to the ICU, 0.1% (95%CI: 0.0–2.2%) experienced a “severe” outcome and 0.02% (95%CI: 0.001–0.05%) died. Hospital-based screening studies (N = 39) reported that 23.9% (95%CI: 19.0–29.2%) of children were hospitalized, 2.9% (95%CI: 2.1–3.8%) were admitted to the ICU, 1.3% (95%CI: 0.5–2.3%) experienced a severe outcome, and 0.2% (95%CI: 0.02–0.5%) died. Studies of hospitalized children (N = 31) reported that 10.1% (95%CI: 6.1–14.9%) of children required ICU admission, 4.2% (95%CI: 0.0–13.8%) had a severe outcome and 1.1% (95%CI: 0.2–2.3%) died. Low risk of bias studies, those from high-income countries, and those reporting outcomes later in the pandemic presented lower estimates. However, studies reporting outcomes after May 31, 2020, compared to earlier publications, had higher proportions of hospitalized patients requiring ICU admission and experiencing severe outcomes.Conclusion and RelevanceAmong children tested positive for SARS-CoV-2, 3.3% were hospitalized, with rates being higher early in the pandemic. Severe outcomes, ICU admission and death were uncommon, however estimates vary by study population, pandemic timing, study risk of bias, and economic status of the country.Systematic Review RegistrationPROSPERO, identifier [CRD42021260164].

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