key: cord-1012191-xftw8w5n authors: Ono, Rintaro; Hasegawa, Daisuke title: Prevalence and characteristics of Kawasaki disease before and during the COVID-19 pandemic date: 2021-02-06 journal: World J Pediatr DOI: 10.1007/s12519-021-00412-5 sha: 597f477d49926dbc10a4344917f586a88d05a11f doc_id: 1012191 cord_uid: xftw8w5n nan after obtaining written informed consent for the research use from the guardians. Antibodies for SARS-CoV-2 were evaluated using SARS-CoV-2 IgM/IgG (Artron Laboratories Inc. Canada). The sensitivity and specificity of this kit are 98% and 95%, respectively, when analyzed more than 2 weeks after SARS-CoV-2 infection. For a statistical analysis, the monthly incidences of each disease "before" pandemic (2015-2019) and "during" pandemic (2020) were compared using Wilcoxon signed-rank sum test. Our study was approved by the Institutional Review Board at St Luke's International hospital (18-R103, 19-J016). Twenty patients were diagnosed with KD during the COVID-19 pandemic, and 384 were diagnosed between January 2012 and December 2019. The prevalence of KD was comparable between the "before" and "during" COVID-19 pandemic groups (Table 1) . Table 1 illustrates the characteristics of the KD patients. Both groups had similar clinical manifestations, risk scores, and treatment response. No patients of "during" COVID-19 pandemic group exhibited positivity for PCR or antibody testing for SARS-CoV-2. No patients developed toxic shock syndrome or KD-like symptoms, which have been reported as multisystem inflammatory syndrome in children (MIS-C) after SARS-CoV-2 infection in the Western countries, whereas one patient developed KD-shock syndrome prior to the COVID-19 pandemic [4] . MIS-C may be a disease with racial differences because there are very few reports of MIS-C from East Asian countries, such as China and Japan [5, 6] . Another reason that we did not observe patients with MIS-C may be explained by the incidence of COVID-19 in children which was lower in Japan compared with Western countries during the research period. Data from the National Institute of Infectious Diseases of Japan [7] revealed that the occurrence of most of the common infectious diseases among children, such as chickenpox, mumps, infectious gastroenteritis, and group A streptococcal pharyngitis, declined significantly using Wilcoxon signedrank sum test during the COVID-19 pandemic, whereas the incidence of less epidemic diseases, such as bacterial meningitis and exanthema subitum, did not change significantly (Fig. 1) . It is noteworthy that the incidence of KD did not change during the COVID-19 pandemic. Although the number of cases was limited, our study suggested that incidence of KD might not be influenced by prevalence of contagious viral infection. Further study will be required to clarify the association between KD and infections. The transcriptional profile of coronary arteritis in Kawasaki disease Revision of diagnostic guidelines for Kawasaki disease (the 5th revised edition) Efficacy of immunoglobulin plus prednisolone for prevention of coronary artery abnormalities in severe Kawasaki disease (RAISE study): a randomised, open-label, blinded-endpoints trial Kawasaki disease shock syndrome: case report and cytokine profiling Multisystem inflammatory syndrome in children in New York State Multisystem inf lammatory syndrome in U.S. children and adolescents IDWR Surveillance Data Table 2020 week 34 Ethical approval This study was reviewed and approved by the Institutional Review Board at St Luke's International hospital (18-R103, 19-J016). No financial or nonfinancial benefits have been received or will be received from any party related directly or indirectly to the subject of this article.Informed consent Written informed consent was obtained from parents when laboratory testing for research purposes is done.