1 INTRODUCTION
The coronavirus disease 2019 (COVID-19) has led to a global pandemic with significant morbidity and mortality.1 The pediatric population appears to be affected in a much smaller number than adults, with only 1.7% of cases in the United States occurring in children younger than 18. In other European countries, the number of cases in children is less than 2%.2-4 Currently, it is unclear whether this is due to lower infection susceptibility in children or if the asymptomatic disease is much more common in those under the age of 18.5; 6
Significant numbers of children and teenagers, tested positive for COVID-19 antibodies, have developed a severe inflammatory condition with many disease characteristics of Kawasaki syndrome.7 As case reports pile up, the world is suddenly paying attention to this pediatric condition that may be related to COVID-19.8Kawasaki disease is a rare acute pediatric vasculitis, usually involves small to medium-sized arteries in a wide array of organs and tissues, and can cause coronary artery aneurysms, myocardial infarction, and pericarditis.9 It is characterized by fever, exanthema, lymphadenopathy, conjunctival injection, and changes to the mucosa and extremities. Kawasaki disease is relatively uncommon, with an incidence rate of 20.8 per 100,000 in the United States, mainly in children aged five years or younger.10 The etiology of this syndrome remains unknown; however, antigen-driven delayed immune reaction following viral or bacterial infection in genetically susceptible individuals is the current leading hypothesis.9 In the last two decades, the coronavirus family has been proposed to be one of the triggers of Kawasaki syndrome. Human New Haven coronavirus (HCoV-NH) was identified in the respiratory secretions of 72.7% of children with Kawasaki disease11, and positive CoV-229E antibodies was detected by immunofluorescence assay in patients with Kawasaki disease12, eliciting a putative link with COVID-19 disease.
Verdoni et al. described an outbreak of a Kawasaki-like disease occurring in Bergamo, Italy, at the peak of the COVID-19 pandemic.13 As of May 21, other confirmed and suspected children of similar presentations have been reported throughout the United States.14 This Kawasaki-like disease appears to cause a hyperinflammatory shock state. Hypotension with a requirement for fluid resuscitation seems to be common15. Some patients required inotropic support. Also, patients with this syndrome appear to respond well to intravenous immunoglobulin. However, the disease course seems more severe than the typical Kawasaki’s disease as adjunct anti-inflammatory treatments were necessary for several patients, with some requiring high-dose corticosteroids. The use of biologics such as infliximab has also been described.13; 16
Despite these findings, much remains unknown about this rare Kawasaki-like disease. Some children have needed intensive care unit (ICU), others recovered quickly. The goal of this meta-analysis was to summarize the clinical and laboratory features of patients with Kawasaki-like disease diagnosed during the COVID-19 pandemic.