New Onset of Giant Cell Arteritis following ChAdOx1-S (Vaxevria®) Vaccine Administration.

We report a 78-year-old man presenting with persistent headaches in vertex and temporo-parietal area; fatigue, worsening after walking; jaw claudication; scotomas; pharyngodynia; and dry cough after the second dose of the SARS-CoV-2 vaccine (ChAdOx1-S) administration. Laboratory findings showed an elevated C-reactive protein level and FDG-CT PET showed evidence of active large vessel vasculitis with diffuse abnormal artery uptake. Under suspicion of vasculitis, a temporal arteries biopsy was performed; the histopathologic findings demonstrated the transmural inflammatory infiltrate with giant cells, compatible with giant cell arteritis. Although the overall incidence of vaccine-triggered autoimmunity is low, rheumatologists worldwide should be aware of autoimmune diseases as a new potential adverse event of vaccines.