Evidence before this study
The rapid spread of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a global pandemic. Doctors in several countries have suggested that the number of children with multi-system inflammatory symptoms, including Kawasaki disease, was increasing. This suggestion prompted various health authorities in Europe and North America to issue alerts to medical professionals. PubMed articles published up to May 31, 2020 were searched using the terms “Kawasaki disease” AND “coronavirus” OR “COVID-19” OR “virus involvement” OR “SARS-CoV-2”. We identified scattered case reports and an observational cohort study from Italy, indicating a possible link between COVID-19 and Kawasaki disease. Previous studies have suggested that viral infections could be the trigger for Kawasaki disease. Therefore, epidemiological studies are needed to clarify the possible link between SARS-CoV-2 and the onset of Kawasaki disease.
Added value of this study
We did a time series analysis that was based on a retrospective review of Kawasaki disease cases at a French tertiary pediatric center in the past 15 years. The center is located in the Paris region, an epicenter of the country’s COVID-19 outbreak. We found an increase in the incidence of Kawasaki disease during the COVID-19 pandemic. During this period, which included the national blockade, the circulation of all other respiratory viruses fell unprecedentedly. Our observations further suggest that there is an association between SARS-CoV-2 infection and Kawasaki disease. Interestingly, a second significant peak of Kawasaki disease was observed in December 2009, during the H1N1 influenza pandemic. To the best of our knowledge, this is the first study to use a time series analysis over a 15-year period to assess the incidence of Kawasaki disease and concurrent circulating viruses, including SARS-CoV-2.
Implications of all available evidence.
The current SARS-CoV-2 pandemic has been followed by a rapid onset of Kawasaki disease, suggesting that children can develop severe forms of COVID-19. This increase in incidence is similar to the peak of Kawasaki disease that occurred after the 2009 H1N1 influenza pandemic, providing evidence of the role of viral infections in triggering Kawasaki disease. Physicians must prepare to manage an increase in the incidence of Kawasaki disease, depending on the magnitude of their local COVID-19 outbreak.
