ABSTRACT
Background: Pediatric cases of COVID-19 surged in the summer/fall of 2021 coinciding with the SARS-CoV-2 Delta variant. It is unclear whether the Delta variant caused more severe illness among pediatric patients. We leveraged the Children and COVID-19 in Colorado database to determine whether differences exist in demographics, underlying comorbidities, and outcomes among children requiring hospital admission due to the SARS-CoV-2 Delta variant vs. wild type virus. Methods: We performed a retrospective review of children <21 years with symptomatic COVID-19 and detectable SARS-CoV-2 NAAT hospitalized at Children's Hospital Colorado during pre-Delta (Mar-Nov 2020) and Delta (Jun-Sep 2021) periods. We compared variables using Fisher's exact or Pearson's chi square tests for categorical variables and Wilcoxon rank sum tests for continuous variables. Results: There were 119 children hospitalized with symptomatic COVID-19 during the pre-Delta and 137 in the Delta period. There was a slight male predominance in both periods. Children hospitalized during the Delta period were younger, with median (interquartile range) age of 5.9 (1.0-14.5) vs. 12.2 (1.5-16.9) years, p=0.02;and were less likely to identify as Hispanic and Spanish-speaking, compared to the pre-Delta period (Table). There was a trend toward decreasing proportions of hospitalized children with underlying comorbidities in the Delta vs. pre-Delta period (59.1% vs. 69.8%;p=0.07). The most prevalent types of comorbidities were similar between periods;but the proportion of hospitalized immunocompromised patients was lower in the Delta vs. pre-Delta period (p=0.005). Half of all children were overweight/obese in both periods. Similar proportions of hospitalized children required respiratory support in both periods, but more children required intensive care in the Delta vs. pre-Delta periods (36.5% vs. 23.5%, p=0.03). Conclusion: Children hospitalized with the Delta variant of COVID-19 were younger, less likely to be Hispanic, and had fewer comorbidities than children hospitalized with wild type SARS-CoV-2. Children hospitalized with the Delta variant were more likely to require ICU admission compared to children hospitalized with wild type SARS-CoV-2, which may indicate increased severity of the Delta variant in the pediatric population. Close monitoring of pediatric outcomes is needed as new SARS-CoV-2 variants emerge.