Systemic autoinflammatory disease following COVID-19 mRNA vaccine: a severe and rare clinical presentation

SARS-CoV-2 pandemic infection caused thousands of deaths and the vaccination was the life-saving tool but some adverse effects have been also described among patients such as redness at the injection site, fever, fatigue, headache, chills, vomiting, and urticaria. Although rare, some cases of systemic hyperinflammation after vaccination have been reported, highlighting the need for a precocious identification and treatment of severe clinical manifestation. We describe here Adult Onset Still Disease (AOSD) that developed after vaccination with mRNA COVID-19 vaccine and caused a macrophage activation syndrome. The pathogenetic mechanism underlying the occurrence of an autoimmune or autoinflammatory disease after a vaccination has not been yet clarified: a viral infection can trigger autoimmune or autoinflammatory diseases through the mechanisms of the molecular mimicry and the bystander activation.