RESUMEN
ChAdOx1 nCoV-19 is an effective and well-tolerated coronavirus disease 2019 (COVID-19) vaccine. Rare cases of serious adverse events have been reported with this vaccine. We report three patients who developed Guillain-Barré syndrome following ChAdOx1 nCoV-19 vaccination, who did not have active or prior COVID-19 infection. The neurological illness in all patients had an onset of 11-13 days after the first dose of vaccine. All were characterized by sensorimotor weakness of the upper and lower limbs, with facial diplegia in one and dysautonomia in the other. Nerve conduction studies were consistent with demyelination in two and axonopathy in one. Cerebrospinal fluid analysis showed albuminocytological dissociation in two patients. All patients had moderate-to-severe disability. They were treated with intravenous immunoglobulin, with stabilization of the disease. Proper monitoring and prompt reporting of such cases is required to ensure safety of the vaccine.