COVID-19, the omicron variant and its association with croup in
Pediatrics; a single center study in Hong Kong
Background: The 5th wave of the COVID-19 pandemic in Hong Kong
was dominated by the omicron variant, which may have more upper airway
involvement affecting children. This pilot study aims at analyzing any
associations between the COVID-19-omicron-variant and croup in children.
Methods: This retrospective study reviewed electronic medical
records of patients admitted to Tuen Mun Hospital of Hong Kong from 1
January 2018 to 31 March 2022 with diagnostic code of croup (ICD-10 code
J05.0). Patients were categorized into non-COVID period (1 January 2018
- 31 December 2019); COVID-pre-omicron period (1 January 2020 - 31
December 2021) and COVID-omicron period (1 January 2022- 31 March 2022).
Disease associations and severity were compared through incidence rates,
Westley Croup Severity Score, length of hospital stay, medications use,
respiratory support and intensive care unit admissions.
Results: The rate of infection of COVID-19 in croup patients
admitted during COVID-omicron period (90%) was significantly higher
than those in the COVID-pre-omicron period (3.6%, p< 0.001).
They also had a higher Westley Score (moderate + severe disease:
COVID-omicron: 56.7%; COVID-pre-omicron: 22.4%; p=0.004; non-COVID:
24.8%, p< 0.001), longer hospital stay (median: COVID-omicron
3.00 days ; COVID-pre-omicron:2.00 days, p<0.001, non-COVID:
2.00 days, p=0.034) , and higher dexamethasone requirements (mean :
COVID-omicron = 0.78mg/kg; COVID-pre-omicron= 0.49mg/kg, p <
0.001; non-COVID =0.58mg/kg , p=0.001) while compared to those of the
COVID-pre-omicron period and non-COVID period. Conclusion: The
omicron variant of COVID-19 is a significant contributing factor to
croup and can lead to more severe disease in children of Hong Kong.