Kawasaki disease and influenza-new lessons from old associations.

Kawasaki disease (KD), an enigmatic medium vessel vasculitis, presents as an acute febrile illness predominantly affecting young children. KD appears to be a hyper-inflammatory response elicited by environmental or infectious agents (including respiratory viruses) in genetically predisposed individuals. Numerous reports from the current era of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have described the occurrence of KD/KD-like illness in close temporal proximity to SARS-CoV-2 infection or exposure. Notably, KD has been reported in association with H1N1-pdm09 virus that caused the previous pandemic a decade ago. Non-H1N1 influenza infections as well as influenza vaccination have also been reported to trigger KD. Herein, we report a case of H1N1-pdm09 influenza who developed KD. We review the published literature on influenza infection or vaccination triggering KD. This may help in a better understanding of the KD/KD-like illness associated with SARS-CoV-2. Besides, we also evaluate the safety of aspirin in influenza-triggered KD as aspirin administration in children with influenza is associated with the risk of development of Reye syndrome.