PC1023: Association of covid-19-related Croup with sars-cov-2 Variants of Concern

Background: Recent single-center reports demonstrated an association with SARS-CoV-2 and croup prevalence and severity. However, national estimates are lacking. We aimed to describe whether SARS-CoV-2 variants are associated with 1) the proportion of children with croup and 2) hospital and intensive care unit (ICU) admissions, and racemic epinephrine (RE) treatment.

Methods: We conducted a cross-sectional study among children ≥3 months to ≤8 years of age with a diagnoses of COVID-19 and croup between January 1st, 2021 and January 31st, 2022. Data was from the Pediatric Health Information System and Center for Disease Control COVID Data Tracker. The primary exposure was the dominant SARS-CoV-2 variant (alpha, delta, omicron), defined as >50% of SARS-CoV-2 being attributable to a particular variant. The primary outcome was the proportion of children with COVID-19-related croup. Secondary outcomes included, hospital and ICU admissions, and treatment with RE. We used parametric tests and a mixed-effects logistic regression model with random intercept for hospital to generate the predicted probability of hospital admission and treatment with RE, after adjusting for covariates. Intraclass correlation coefficients were used to summarize the proportion of (latent) variation in our outcomes explained by hospital effects.

Results: We identified 74,173 COVID-19 encounters, of which 4,743 (6.4%) had COVID-19-related croup. Of these, 4,442 were included in analysis (median age 17 months [IQR 9, 31], 2,876 [64.8%] male). There were 345 (7.8%), 806 (18.1%), and 3,291 (74.1%) encounters during alpha, delta and omicron variant predominance, respectively (Table 1). The proportion of children with COVID-19-related croup encounters increased significantly during omicron (73.6%) compared to alpha (8.0%) and delta (18.5%) periods (Figure 1; p< 0.001). The probability of hospitalization was not significantly different during omicron (19.4%, 95% CI: 16.1, 22.7) compared to alpha/other (23.8%, 95% CI: 18.2, 29.3) or delta (18.7%, 95% CI: 14.8, 22.7). The proportion of encounters requiring RE was significantly higher during omicron (35.0%) and alpha/other (36.7%) compared to delta (28.2%) predominance (p=0.001), although the median number of doses was not statistically different (p=0.88), nor was ICU admission (p=0.53). The probability of receiving any nebulized RE was significantly higher during omicron (37.1% [95% CI: 32.6, 41.5]; p=0.001) and alpha/other (38.0% [95% CI: 31.6, 44.4]; p=0.014), compared to delta predominance (30.7% [95% CI: 25.8, 35.7]). Hospital effects explained 9.8% (95% CI: 5.5, 16.8) of the variation of hospital admission and 10.1% (95% CI: 5.8, 16.9) of the variation of receiving RE.

Conclusion: Encounters and treatment with RE for COVID-19-related croup increased significantly during omicron, although hospitalizations and ICU admissions did not change. Our findings may be of interest to pediatric health systems, particularly EDs, as they prepare for viral respiratory seasons.