eosinophilic granulomatosis with polyangiitis; Severe motor sensory axonal polyneuropathy in a patient with eosinophilic granulomatosis with polyangiitis post COVID-19 vaccination; This is a literature report.   A 61-year-old woman with a history of asthma and hypothyroidism received her second dose of the Pfizer- BioNTech COVID-19 (BNT162b2) vaccine in the spring of 2021. Her post-vaccination period after the first dose of Pfizer vaccine was unremarkable. The day after her second injection she experienced ten days of fever and malaise that kept her in bed followed by distal pain and weakness in her left hand spreading over the next two weeks to her right hand and both lower legs. She was admitted to an outside hospital 28 days after receiving the second dose of vaccine. Lumbar puncture and MRI of the brain at that time were unremarkable. She was treated with 1 gram of intravenous methylprednisolone per day for four days and a subsequent short oral steroid taper with only marginal improvement. At 64 days after the second vaccine dose, her weakness was progressing and she developed transient, left painless, monocular vision loss leading to her admission to PRIVACY hospital. On admission, her vital signs were blood pressure 134/71 mm/Hg, pulse 81 beats/minute, temperature 97.2 Fahrenheit, respiratory rate 21 breaths/minute, SpO2 97%, and body mass index (BMI) 21.61 kg/m2. Her general exam revealed her lungs to be clear to auscultation. Purpuric lesions developed on her ankles several days after admission. Her neurologic exam was notable for approximately 2/5 strength distally (movement with gravity eliminated), 3+/5 strength proximally (movement against gravity but not mild resistance), absent deep tendon reflexes except for left patellar trace reflex and moderately severe sensory loss to pin prick, vibration, and proprioception in a stocking and glove distribution. Carotid ultrasound did not show any significant atherosclerosis. A computerized tomography (CT) exam of the head revealed severe paranasal sinus disease and chest CT showed multiple pulmonary nodules bilaterally along with bronchial disease. Her serum sodium on admission was 120 mmol/L, felt secondary to poor oral intake. Her white blood cell count was over 21460 per microliter and her absolute eosinophil count was 7570 cells per microliter of blood. The inflammatory markers erythrocyte sedimentation rate (ESR) and C-reactive protein were elevated at 47 mm/h and 139 mg/L respectively. Myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) was positive. Echocardiogram was unremarkable except for sinus tachycardia and frequent periventricular contractions (PVC's). Electromyogram/nerve conduction study revealed severe axonal polyneuropathy in the upper and lower extremity muscles. Skin biopsies were performed of purpuric lesions on the right ankle, combined with biopsy of the sural nerve. The skin biopsy revealed cutaneous small vessel vasculitis. The sural nerve biopsy revealed eosinophil-rich inflammation extensively infiltrating the epineural connective tissue, blood vessels, perineurium and endoneurium along with luminal thrombus formation. Cerebrospinal Fluid (CSF): nucleated cell count was 2 cells per high power field, total protein 20 mg/dL, glucose 54 mg/dL. Creatinine: 0.36 mg/dL. Cytoplasmic Antineutrophil Cytoplasmic Antibody (C-ANCA): negative. Her initial diagnosis was a COVID-19 vaccine-related acute to chronic inflammatory demyelinating polyneuropathy (A/CIDP) and she was given four plasma exchange treatments without improvement. The biopsy findings combined with eosinophilia and MPO-ANCA positivity confirmed the diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) and she received four days of methylprednisolone 1 gram IV per day. At discharge, her eosinophilia had resolved, and she was started on prednisone daily (1 mg/kg dosing) based on her Five-Factor Score of 1 (central nervous system involvement) with the recommendations to continue this dose until outpatient Rheumatology follow-up. She continued physical therapy as an outpatient. At her most recent rheumatology clinic appointment, two years after her vaccination, she was walking with ankle-foot prostheses and had limited ability to grasp with her hands. Her current treatment is methotrexate 20 mg weekly and prednisone 10 mg daily.   In conclusion, this report adds to prior case reports from the past two years describing activation of EGPA following COVID-19 mRNA vaccination. Causality assessment for AEFI was not done using the World Health Organization-Adverse Events Following Immunization (WHOAEFI) causality assessment scale. The sequence of events, however, is suggestive that EGPA was precipitated post-COVID-19 vaccination. Though PNS involvement is common in EGPA, it is remarkable that our patient showed a severity of PNS involvement that is rare in EGPA. This presentation mimicked A/CIDP and misled her health care providers (see initial management at the outside hospital) while also raising the question whether vaccine activation of EGPA caused the increased severity of PNS involvement. The purpose of this case report is to create awareness among health care professionals to consider COVID-19 vaccine-induced EGPA in their differential diagnosis of patients presenting with severe progressive weakness in their extremities with eosinophilia, thus avoiding delay in diagnosis and improving patient outcomes. This report, in combination with the other post-vaccination EGPA reports, strongly supports the inclusion of EGPA in the differential of post-vaccination adverse effects.; Sender's Comments: Based on the available information, a causal relationship between the reported events Eosinophilic granulomatosis with polyangiitis, Peripheral sensorimotor neuropathy and suspect product cannot be excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.