Classification of SARS-CoV-2 Pediatric Hospitalizations: Delta vs Omicron Variant

To classify COVID-19 pediatric hospitalizations based on reason for admission ("for COVID" or "with COVID") and to compare disease severity and age between the delta and omicron variant predominant time frames.

This was a retrospective study in patients aged ≤18 years who were hospitalized at a large, tertiary care pediatric hospital for COVID-19 from July 2021 to February 2022. Disease severity was determined based on length of stay, PICU admission, and Remdesivir receipt. A χ2 analysis and a Cochran-Mantel-Haenszel test were used to analyze relationships between presumed variant type with admission reason, disease severity, and age.

There were 492 patients included with more admissions during the omicron variant predominant time frame (n = 307). More patients were admitted "for COVID" during the delta variant predominant time frame compared with the omicron variant predominant time frame (P < .001) with interrater reliability testing indicating substantial agreement between reviewers. PICU admissions (P < .001), receipt of remdesivir (P < .001), and length of stay (P < .001) were greater during the delta variant predominant time frame. Hospitalizations "for COVID" were more common in patients aged <5 years during both the delta (odds ratio, 2.6; 95% confidence interval, 1.2-5.7) and omicron (odds ratio, 5.7; 95% confidence interval, 3.4-9.4) predominant time frames compared with older patients.

There was a higher proportion of symptomatic COVID-19 hospitalizations with higher disease severity during the delta variant predominance, indicating greater disease severity during earlier periods of the pandemic despite lower hospitalization rates.