Pediatric Croup Due to Omicron Infection Is More Severe Than Non-COVID Croup

Objective: Croup due to infection with the omicron variant of COVID is an emerging clinical entity, but distinguishing features of omicron croup have not yet been characterized. We designed a study to compare the clinical features of croup patients presenting to the pediatric emergency department pre-COVID pandemic with COVID-positive croup patients who presented during the initial omicron surge.

Methods: This was a retrospective observational cohort study of children 0 to 18 years old who presented to our urban, tertiary care pediatric emergency department with symptoms of croup. The study compared a cohort of croup patients who presented in the year before the onset of the COVID pandemic to a cohort of COVID-positive croup patients who presented during the initial omicron surge. The primary outcomes included illness severity and treatments required in the emergency department. The secondary outcome was hospital admission rate.

Results: There were 499 patients enrolled in the study, 88 in the omicron croup cohort and 411 in the classic croup cohort. Compared with the classic croup patients, omicron croup patients were more likely to present with stridor at rest (45.4% vs 31.4%; odds ratio [OR], 1.82; confidence interval [CI], 1.14-2.91) and hypoxia (3.4% vs 0.5%; OR, 7.22; CI, 1.19-43.86). Omicron croup patients required repeat dosing of inhaled epinephrine in the emergency department more often (20.4% vs 6.8%; OR, 3.51; CI, 1.85-6.70), and they were more likely to require respiratory support (9.1% vs 1.0%; OR, 10.18; CI, 2.99-34.60). Admission rates were significantly higher for omicron croup patients than for classic croup patients (22.7% vs 3.9%; OR, 7.26; CI, 3.58-14.71), and omicron croup patients required intensive care more frequently (5.7% vs 1.5%; OR, 4.07; CI, 1.21-13.64).

Conclusions: Pediatric patients with omicron croup develop more severe disease than do children with classic croup. They are more likely to require additional emergency department treatments and hospital admission than patients with croup before the COVID pandemic.