Trends in Pediatric Hospital Admissions Caused or Contributed by SARS-CoV-2 Infection in England

Objective: To investigate the changing characteristics of SARS-CoV-2-related pediatric hospital admissions over time.

Study design: This was a national, observational cohort study from July 1, 2020, to August 31, 2023, using English population-linked electronic health records. We identified 45 203 children younger than 18 years old in whom SARS-CoV-2 either caused or contributed to hospitalization, excluding those admitted with "incidental" infection. Studied outcomes were types of hospitalization and severe hospitalizations involving either critical care or pediatric inflammatory multisystem syndrome-temporally associated with SARS-CoV-2 (PIMS-TS).

Results: There were 45 920 SARS-CoV-2-related hospitalizations in children: 34 870 (75.9%) attributable to COVID-19; 1845 (4.0%) attributable to PIMS-TS; 8330 (18.1%) with SARS-CoV-2 as contributor to admission; and 875 (1.9%) acquired nosocomial SARS-CoV-2 infection. The most notable changes between the first 3 waves (March 2020 through November 2021) and the Omicron era (December 2021 onwards) were a decrease in PIMS-TS from 1575 of 14 020 (11.2%) to 270 of 31 905 (0.8%); a reduction in critical care use from 1175 of 14 020 (8.4%) to 1390 of 31 905 (4.4%); a decreased in mortality rate among those hospitalized from 521 per 100 000 to 249 per 100 000; and a decrease in the median age of hospitalized children from 4.7 (IQR 0.6,12.3) to 1.1 (IQR 0.3,6.4) years. Of children hospitalized, infants, 10.2% of whom had a recorded underlying health condition, comprised 4225 of 14 020 (30.1%) admissions 2020 through 2021 and 15 555 of 31 900 (48.8%) since 2022. (P < .001 for all comparisons).

Conclusions: Infants are now the pediatric age group most affected by SARS-CoV-2, at least partially because they have the least immunity to the virus, and are most vulnerable to respiratory illnesses.