Importance: Investigating how the risk of serious illness after SARS-CoV-2 infection in children and adolescents has changed as new variants have emerged is essential to inform public health interventions and clinical guidance.
Objective: To examine risk factors associated with hospitalization for COVID-19 or pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) among children and adolescents during the first 2 years of the COVID-19 pandemic and change in risk factors over time.
Design, setting, and participants: This population-level analysis of hospitalizations after SARS-CoV-2 infection in England among children and adolescents aged 0 to 17 years was conducted from February 1, 2020, to January 31, 2022. National data on hospital activity were linked with data on SARS-CoV-2 testing, SARS-CoV-2 vaccination, pediatric intensive care unit (PICU) admissions, and mortality. Children and adolescents hospitalized with COVID-19 or PIMS-TS during this time were included. Maternal, elective, and injury-related hospitalizations were excluded.
Exposures: Previous medical comorbidities, sociodemographic factors, and timing of hospitalization when different SARS-CoV-2 variants (ie, wild type, Alpha, Delta, and Omicron) were dominant in England.
Main outcomes: PICU admission and death within 28 days of hospitalization with COVID-19 or PIMS-TS.
Results: A total of 10 540 hospitalizations due to COVID-19 and 997 due to PIMS-TS were identified within 1 125 010 emergency hospitalizations for other causes. The number of hospitalizations due to COVID-19 and PIMS-TS per new SARS-CoV-2 infections in England declined during the second year of the COVID-19 pandemic. Among 10 540 hospitalized children and adolescents, 448 (4.3%) required PICU admission due to COVID-19, declining from 162 of 1635 (9.9%) with wild type, 98 of 1616 (6.1%) with Alpha, and 129 of 3789 (3.4%) with Delta to 59 of 3500 (1.7%) with Omicron. Forty-eight children and adolescents died within 28 days of hospitalization due to COVID-19, and no children died of PIMS-TS (PIMS-S data were limited to November 2020 onward). Risk of severe COVID-19 in children and adolescents was associated with medical comorbidities and neurodisability regardless of SARS-CoV-2 variant. Results were similar when children and adolescents with prior SARS-CoV-2 exposure or vaccination were excluded.
Conclusions: In this study of data across the first 2 years of the COVID-19 pandemic, risk of severe disease from SARS-CoV-2 infection in children and adolescents in England remained low. Children and adolescents with multiple medical problems, particularly neurodisability, were at increased risk and should be central to public health measures as further variants emerge.