Inflammatory demyelinating polyneuropathy after the ChAdOx1 nCoV-19 vaccine may follow a chronic course

BACKGROUND: Rare autoimmune neurological events have been reported during the ongoing global drive for mass vaccination as a means of controlling the Covid-19 pandemic. Guillain-Barré syndrome, an acute inflammatory neuropathy well recognised as a rare complication of influenza vaccination, has been reported to follow administration of the ChAdOx1 nCoV-19 (AstraZeneca) vaccine. METHODS: We report four patients with inflammatory demyelinating polyneuropathy after vaccination in whom a relapsing or progressive course indicated the development of chronic inflammatory demyelinating polyneuropathy (CIDP). CONCLUSIONS: Awareness of this complication and distinction from Guillain-Barré syndrome enables the timely institution of maintenance immunomodulatory treatment. Our report also highlights the likely relationship between vaccination and the subsequent development of CIDP, but definitive demonstration of a causal link needs larger studies.