141 - Declining Incidence of Kawasaki Disease Amidst the COVID-19 Pandemic in Taiwan: A Time Series Analysis

Poster Number: 141
Publication Number: 141.3000

Background: Kawasaki disease (KD) is an acute systemic vasculitis involving coronary artery that mainly affects children under 5 years of age, with still unclear etiology. In 2020, Taiwanese experienced a dramatic life-style change including social distance, mask wearing and school closure, although domestic coronavirus disease 2019 (COVID-19) cases are extremely low.

Objective: To investigate the epidemiology and possible triggers of KD without interference of MIS-C.

Design/Methods: This is a nationwide and retrospective ecological study using National Health Insurance Research Database (NHIRD) of Taiwan, to detect the change of KD incidence trend in children less than 5 years old during the period social distancing policy in 2020. Time series analysis through ARIMA (Autoregressive Integrated Moving Average) model was used based on the seasonal variation and increasing trend of KD incidence over the past 10 years prior to COVID-19 pandemic. We also compared that with the timeline of COVID-19 mitigation measures, population mobility trend, and other common pediatric infectious diseases to figure out the possible etiology of KD.

Results: The predicted monthly incidence (95% CI) of KD in April, May, and June 2020 were 5.26 (3.58-6.94), 5.45 (3.70-7.20), and 5.41 (3.61-7.21) per 100,000 person-month. The actual observed incidences were 2.41, 2.67, 2.60 per 100,000 person-month, respectively, representing a 51.2%, 51.0%, and 51.9% reduction in incident rates in these 3-month period of COVID-10 mitigation measures. There is a rebound peak in July 2020, coincident with the lift of social distancing policy.

Conclusion(s): KD incidence decreased by approximately 50% during the period of COVID-19 mitigation measures in 2020 in Taiwan. The trend was not proportionate to the profound decline of common infectious cases, which suggest that human-to-human contact may be a potential KD trigger, but there are factors other than infection should have contributed.