154 - KAWASAKI DISEASE VERSUS RESPIRATORY VIRAL ACTIVITY DURING THE COVID-19 PANDEMIC

Background: Although the etiology of Kawasaki Disease (KD) is yet to be elucidated, the possibility of a respiratory viral trigger has been reported. Temporal and seasonal clustering have also been well described suggesting a respiratory portal of entry. We examined the disrupted respiratory viral seasonality during the COVID-19 pandemic in relation to KD epidemiology during this time.

Methods: Retrospective chart review of cases from Jan 1, 2019 until Dec 31, 2023 with the discharge diagnosis of KD. Viral surveillance data for Respiratory Syncytial Virus (RSV), Influenza A & B and COVID was reviewed for the same period including tests from Emergency Room and inpatient locations.  Coronary artery involvement (CAI) was defined as a z score >2.

Results: During the study period, there were 216 cases of KD (Table 1). In 2020, the majority of cases (22/34,64%) presented prior to the widespread lockdown (3/19/2020). It was also the only year with a female preponderance of subjects (18F:16M: 1.13:1). The average ages in 2020 and 2021 (25.5 and 24.1 months respectively) were younger but reverted to pre-pandemic average age (34.9m) by 2023. 2021 had the youngest average age group and the highest percentage of CAI (39%).  Using Influenza and RSV as proxies for viral activity, there was a sharp decline in viral activity after the widespread lockdown in early 2020, with later peaks in virus activity. There was no direct correlation between these peaks and KD cases, though seasonality normalized as did KD activity by the end of the study period.

Conclusion: At the onset of COVID lockdown, transmission of respiratory viruses declined as did KD cases. There was a more pronounced drop in KD cases after the first lockdown when schools remained closed and less impact after the second lockdown when schools remained in session.  During the pandemic, the average age decreased with more cases in female subjects.  As restrictions lifted, respiratory viral activity began to normalize as did KD epidemiology supporting previous observations suggesting the possibility of a respiratory viral trigger in KD.