Kawasaki disease following SARS-CoV-2 infection: Stronger inflammation with no increase in cardiac complications.

Background:Herein we investigate the difference between Kawasaki disease (KD) with and without a recent history of SARS-CoV-2 infection. Methods:We compared the clinical characteristics of patients with KD during the SARS-CoV-2 pandemic in a single children's hospital in Korea. Fifty-two patients were enrolled and divided into group 1 (with a history of COVID-19, n = 26) and group 2 (without a history of COVID-19, n = 26) according to whether or not they contracted COVID-19 within the 8 weeks before hospitalization. Data, including clinical features and laboratory results, were analyzed and compared between groups. Results:The median age of patients was significantly higher in group 1 than in group 2 (53 months [IQR, 24-81] vs. 15 months [IQR, 6-33], p = 0.001). The incidence of cervical lymphadenopathy was significantly higher (p = 0.017), while that of BCGitis was significantly lower in group 1 (p = 0.023), and patients had a significantly longer hospital stay (5 days [IQR, 3-8] vs. 3 days [IQR, 3-4], p = 0.008). In group 1, platelet count was significantly lower (p = 0.006), and hemoglobin and ferritin levels were significantly higher (p = 0.013 and p = 0.001, respectively) on the first admission day. Following treatment with intravenous immunoglobulin (IVIG), the platelet count was significantly lower (p = 0.015), and the percentage of neutrophils and neutrophil-to-lymphocyte ratio were significantly higher in group 1 (p = 0.037 and p = 0.012). Although there was no statistical difference, patients requiring infliximab treatment due to prolonged fever was only in group 1. The incidence of cardiovascular complications did not differ between the groups. Conclusions:Post-COVID KD showed a stronger inflammatory response than KD-alone, with no differences in cardiac complications.