Changing Characteristics of Children With COVID-19 in Colorado Admitted During Different Variant Periods.

BACKGROUND: Data are lacking on the impact of different severe acute respiratory syndrome coronavirus 2 variants in children and on pediatric vaccine effectiveness. We examined differences among children requiring hospital admission associated with coronavirus disease 2019 (COVID-19) during wild type, Delta and Omicron variant periods and calculated vaccine effectiveness at preventing symptomatic hospitalization during the Delta and Omicron variant periods. METHODS: We conducted a retrospective review of children younger than 21 years of age hospitalized with symptomatic COVID-19. Characteristics were compared between variant periods using Kruskal-Wallis or generalized Fisher exact tests. We estimated vaccine effectiveness in preventing symptomatic hospitalization. RESULTS: We included 115 children admitted during the wild type period, 194 during Delta and 226 during the Omicron periods. Median age (years) decreased (12.2 wild type, 5.9 Delta, 1.3 Omicron periods, P < 0.0001) over time. Children were less likely to have a comorbid condition, including diabetes or obesity, and had shorter admissions during Omicron compared with the wild type and Delta periods. Intensive care unit admissions and respiratory support requirements were highest during the Delta period (P = 0.05). Among children ≥12 years, adjusted vaccine effectiveness at preventing symptomatic hospitalization was 86% during Delta and 45% during Omicron periods. CONCLUSIONS: Children hospitalized with COVID-19 during later variant periods were younger and less likely to have comorbidities. Children admitted during the Delta variant period required more intensive care and respiratory support compared to other variant periods. Vaccination was less effective at preventing symptomatic hospital admission during the Omicron period compared to the Delta period.

Risk Factors for Severe COVID-19 in Children.

BACKGROUND: There are limited pediatric data regarding severe COVID-19 disease. Our study aims to describe the epidemiology and identify risk factors for severe COVID-19 disease in children. METHODS: This is a retrospective cohort study among children with positive SARS-CoV-2 PCR from March to July 2020 at Children's Hospital Colorado. Risk factors for severe disease were analyzed as defined by hospital admission, respiratory support, or critical care. Univariable and multivariable analyses were conducted. RESULTS: Among 454 patients identified with SARS-CoV-2, 191 (42.1%) were females, median age 11 years. Fifty-five percent of all patients identified as Hispanic compared with 29% among all hospital visits in 2019 (P < 0.0001). In multivariable analyses, age 0-3 months or >20 years [adjusted odds ratio (aOR), 7.85; P < 0.0001 and aOR, 5.1; P = 0.03, respectively], preterm birth history (aOR, 3.7; P = 0.03), comorbidities [including immunocompromise (aOR, 3.5; P = 0.004), gastrointestinal condition (aOR, 2.7; P = 0.009), diabetes (aOR, 6.6; P = 0.04), asthma (aOR, 2.2; P = 0.04)], and specific symptoms at presentation were predictors for admission. Age 0-3 months or >20 years, asthma, gastrointestinal condition, and similar symptoms at presentation were also predictors for respiratory support. Elevated C-reactive protein was associated with the need for critical care with median of 17.7 mg/dL (IQR, 5.3-22.9) versus 1.95 mg/dL (IQR, 0.7-5.5) among patients requiring critical versus no critical care (OR, 1.2; P = 0.02). CONCLUSIONS: Extremes of age, comorbid conditions, and elevated CRP are predictors of severe disease in children. Findings from this study can inform pediatric providers and public health officials to tailor clinical management, pandemic planning, and resource allocation.

Comparison of Upper Respiratory Viral Load Distributions in Asymptomatic and Symptomatic Children Diagnosed with SARS-CoV-2 Infection in Pediatric Hospital Testing Programs.

The distribution of upper respiratory viral loads (VL) in asymptomatic children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. We assessed PCR cycle threshold (Ct) values and estimated VL in infected asymptomatic children diagnosed in nine pediatric hospital testing programs. Records for asymptomatic and symptomatic patients with positive clinical SARS-CoV-2 tests were reviewed. Ct values were (i) adjusted by centering each value around the institutional median Ct value from symptomatic children tested with that assay and (ii) converted to estimated VL (numbers of copies per milliliter) using internal or manufacturer data. Adjusted Ct values and estimated VL for asymptomatic versus symptomatic children (118 asymptomatic versus 197 symptomatic children aged 0 to 4 years, 79 asymptomatic versus 97 symptomatic children aged 5 to 9 years, 69 asymptomatic versus 75 symptomatic children aged 10 to 13 years, 73 asymptomatic versus 109 symptomatic children aged 14 to 17 years) were compared. The median adjusted Ct value for asymptomatic children was 10.3 cycles higher than for symptomatic children (P < 0.0001), and VL were 3 to 4 logs lower than for symptomatic children (P < 0.0001); differences were consistent (P < 0.0001) across all four age brackets. These differences were consistent across all institutions and by sex, ethnicity, and race. Asymptomatic children with diabetes (odds ratio [OR], 6.5; P = 0.01), a recent contact (OR, 2.3; P = 0.02), and testing for surveillance (OR, 2.7; P = 0.005) had higher estimated risks of having a Ct value in the lowest quartile than children without, while an immunocompromised status had no effect. Children with asymptomatic SARS-CoV-2 infection had lower levels of virus in their nasopharynx/oropharynx than symptomatic children, but the timing of infection relative to diagnosis likely impacted levels in asymptomatic children. Caution is recommended when choosing diagnostic tests for screening of asymptomatic children.