ANCA-Associated Vasculitis; nausea; vomiting; diarrhea; lethargy; This is a literature report following Pfizer-BioNTech COVID-19 Vaccine.  A 78-year-old woman with a past medical history of type 2 diabetes mellitus, hypertension, and paroxysmal atrial fibrillation received her first dose of the Pfizer-BioNTech COVID-19 vaccine in early February 2021, after which she developed nausea, vomiting, and diarrhea. Routine laboratory assessments obtained 16 days after vaccination were notable for a serum creatinine level (Scr) of 1.31 mg/dL and urinalysis with blood (3+), 99 red blood cells (RBCs) per high-power field, 7 white blood cells (WBCs) per highpower field, and 100 mg/dL protein. Routine laboratory assessments obtained a few weeks prior to vaccination were notable for an Scr of 0.77 mg/dL and urinalysis with absent hematuria and proteinuria. Her symptoms improved spontaneously, and she received the second dose of the Pfizer-BioNTech COVID-19 vaccine 22 days after the first injection. After the second dose, she once again noted symptoms of nausea, vomiting, and diarrhea, as well as new-onset lethargy. At the time of presentation, 28 days after the first vaccine dose, laboratory assessments were notable for an Scr of 3.54 mg/dL and urinalysis with blood (3+), 56 RBCs per high-power field, 13 WBCs per highpower field, and 100 mg/dL protein. The patient had no documented history of COVID-19. She was referred to the emergency department, where computed tomography of the abdomen and pelvis showed no acute abnormality. She was started on intravenous crystalloid, without improvement in Scr, prompting nephrology consult. A manual urine microscopy revealed 1-2 granular casts per high-power field, few renal tubular epithelial cells, too-numerous-to-count RBCs (>10% dysmorphic), and few WBCs. Random urinary albumincreatinine ratio was 2.05 g/g. The patient was found to have an elevated titer of anti-MPO antibody (titer: 1.1 AI; normal: <0.2 AI). Complement levels and other serologic tests were unremarkable. She was started on intravenous methylprednisolone for 3 days and prednisone 1 mg/kg daily after that. Kidney biopsy revealed crescentic necrotizing glomerulonephritis with moderate interstitial inflammation on light microscopy. Immunofluorescence confirmed pauciimmune glomerulonephritis. She was diagnosed with renal-limited MPO-AAV and she was started on rituximab. Her Scr improved to 2.25 mg/dL at the time of discharge and 1.71 mg/dL at the 1 month follow-up. Other lab tests included Serum bicarbonate (22-32 mEq/l): 29 (Days Relative to First Vaccine Dose at -21), 30 (Days Relative to First Vaccine Dose at +16), 26 (Days Relative to First Vaccine Dose at +28); Serum chloride (98-110 mEq/l): 97 (Days Relative to First Vaccine Dose at -21), 100 (Days Relative to First Vaccine Dose at +16), 97 (Days Relative to First Vaccine Dose at +28); Serum creatinine (0-4.1 mg/dl): 0.77 (First Vaccine Dose at -21; Routine laboratory assessments obtained a few weeks prior to vaccination were notable for an Scr of 0.77 mg/dL), 1.31 (after vaccination were notable for a serum creatinine level (Scr) of 1.31 mg/dL), 3.54 (Days Relative to First Vaccine Dose at +28), 2.25 (Her Scr improved to 2.25 mg/dL at the time of discharge), 1.71 (1.71 mg/dL at the 1 month follow-up), Serum potassium (3.6-5.1 mEq/l): 4.2 (Days Relative to First Vaccine Dose at -21), 4.5 (Days Relative to First Vaccine Dose at +16), 4.5 (Days Relative to First Vaccine Dose at +28); Serum sodium (135-145 mEq/l): 135 (Days Relative to First Vaccine Dose at -21), 136 (Days Relative to First Vaccine Dose at +16), 135 (Days Relative to First Vaccine Dose at +28), SUN (6-24 mg/dl): 18 (Days Relative to First Vaccine Dose at -21), 22 (Days Relative to First Vaccine Dose at +16), 42 (Days Relative to First Vaccine Dose at +28), Blood/Urinalysis: Negative (Days Relative to First Vaccine Dose at -21), 3+ (Days Relative to First Vaccine Dose at +16), 3+ (Days Relative to First Vaccine Dose at +28), Glucose: Negative (Days Relative to First Vaccine Dose at -21), Negative (Days Relative to First Vaccine Dose at +16), Negative (Days Relative to First Vaccine Dose at +28), Nitrite level: Negative (Days Relative to First Vaccine Dose at -21), Negative (Days Relative to First Vaccine Dose at +16), Negative (Days Relative to First Vaccine Dose at +28), Protein (-10 mg/dl): Negative (Days Relative to First Vaccine Dose at -21), 100 (Days Relative to First Vaccine Dose at +16), 100 (Days Relative to First Vaccine Dose at +28), RBCs per HPF (0-5): 0 (Days Relative to First Vaccine Dose at -21; unit: /HPF), 99 (Days Relative to First Vaccine Dose at +16), 56 (Days Relative to First Vaccine Dose at +28), Specific gravity (1.010-1.030): 1.021 (Days Relative to First Vaccine Dose at -21), 1.013 (Days Relative to First Vaccine Dose at +16), 1.017 (Days Relative to First Vaccine Dose at +28), Ketones: Negative (Days Relative to First Vaccine Dose at -21), Negative (Days Relative to First Vaccine Dose at +16), 2+ (Days Relative to First Vaccine Dose at +28), Leukocyte esterase: Negative (Days Relative to First Vaccine Dose at -21), Trace (Days Relative to First Vaccine Dose at +16), Negative (Days Relative to First Vaccine Dose at +28), WBCs per HPF (0-6): 0 (Days Relative to First Vaccine Dose at -21; Unit: /HPF), 7 (Days Relative to First Vaccine Dose at +16), 13 (Days Relative to First Vaccine Dose at +28).; Sender's Comments: Based on the available information and the strong drug event temporal association, a possible contributory role of suspect product BNT162B2 to development of event Anti-neutrophil cytoplasmic antibody positive vasculitis 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.