acute renal failure; ANCA-Associated Vasculitis following the First Dose of Pfizer-BioNTech COVID-19 Vaccine; This is a literature report.  A 47-year-old female patient received BNT162b2 (BNT162B2), as dose 1, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. The following information was reported: ACUTE KIDNEY INJURY (medically significant), 3 days after the suspect product(s) administration, outcome "unknown", described as "acute renal failure"; ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODY POSITIVE VASCULITIS (medically significant), 3 days after the suspect product(s) administration, outcome "unknown", described as "ANCA-Associated Vasculitis following the First Dose of Pfizer-BioNTech COVID-19 Vaccine". The patient underwent the following laboratory tests and procedures: Antineutrophil cytoplasmic antibody: Positive; Biopsy: Pauci-immune crescentic glomerulonephritis; Biopsy kidney: revealed changes of fibrous crescents with, notes: interstitial fibrosis and tubular atrophy with negative immunofluorescence compatible with a systemic disease mediated by ANCA; Blood creatinine: 2.91 mg/dl; 2.01 mg/dl; 1.23 mg/dl; Blood immunoglobulin G: Positive; Blood immunoglobulin G (normal high range 1): 2.8 IU/ml; Blood pressure measurement: 129/76 mmHg; Blood urea: 208 mg/dl; Computerised tomogram: Negative; C-reactive protein (0.8-1.0): 2.34 mg/dl; EGFR status assay: 18, notes: Units: mL/min/1.73 m2; Full blood count: significant; examination: unremarkable; significant for bilateral lower extremity edema, notes: reaching the knees; Red blood cell sedimentation rate: Negative; Serology test: unremarkable; Urine analysis: positive; Urine protein/creatinine ratio: 1777 mg/g, notes: elevated; 861 mg/g; Vital signs measurement: normal; White blood cell count: 14.99 10 3/mm3. Therapeutic measures were taken as a result of acute kidney injury, anti-neutrophil cytoplasmic antibody positive vasculitis. Clinical course:  A healthy 47-year-old woman who developed acute renal failure few days following the Pfizer-BioNTech COVID-19 vaccine. This patient was successfully treated with oral corticosteroids and azathioprine. The patient presented to the primary care clinic for bilateral flank pain, generalized weakness, and bilateral lower extremity swelling that started 3 days following the first dose of Pfizer-BioNTech COVID-19 vaccine. No shortness of breath or hemoptysis was reported. The patient had Bilateral flank pain, generalized weakness, and bilateral lower extremity edema three days after the First dose, with WBC as 14,990/uL, Creatinine as 2.91 mg/dL and Urine protein/creatinine 1777 ug/mg, Serology was Anti-MPO 2.8 IU/ mL. In the Biopsy Pauci-immune crescentic glomerulonephritis was shown. Creatinine was 2.01 mg/dL, Negative CRP, Negative ESR for Two weeks. Observation were two glomeruli are globally obsolescent (sclerosed) with capillary tuft of glomeruli with cellular crescents showing few or no inflammatory cell elements and on periodic acid-Schiff stain, the glomerular basement membranes of unaffected segments show wrinkling and thickening of the glomerular basement membrane. Tubules reveal focal atrophy and interstitium is minimally infiltrated by chronic inflammatory cells. Vital signs were within normal limits, including a blood pressure of 129/76 mm Hg. Physical examination was significant for bilateral lower extremity edema reaching the knees. No sacral edema was noted. Costovertebral angle tenderness was negative. Otherwise, the examination was unremarkable, including a regular rate rhythm, with normal S1 and S2, no murmurs, and palpable peripheral pulses. Urinalysis was positive for proteins, red blood cells of 40-50/ high power field, and white blood cells of 8-10/high power field. Urine protein/creatinine ratio was significantly elevated at 1777 mg/g. Laboratory investigations were compatible with acute kidney injury as the serum creatinine was 2.91 mg/dL (baseline 0.8 mg/dL measured 7 months prior to presentation), urea was 208 mg/dL, and eGFR was 18 mL/min/1.73 m2. In addition, bicarbonate was decreased at 17 mEq/L. The complete blood count was significant for leukocytosis (white blood count 14.99 103/uL) with neutrophil predominance of 82.8%. Inflammatory markers were elevated with C-reactive protein of 2.34 mg/dL (normal range: 0.8-1.0 mg/dL). The extractable nuclear antigen profile was positive for anti-neutrophil cytoplasmic antibody (ANCA) IgG myeloperoxidase (MPO) at 2.8 units/mL (normal <1 units/mL). The IgG class ANCA directed to proteinase 3 (PR3) titers were within normal limits (normal <1 units/mL). Complement levels and other serologic tests were unremarkable. A CT scan of the chest was negative for any lung involvement. A kidney biopsy revealed changes of fibrous crescents with interstitial fibrosis and tubular atrophy with negative immunofluorescence compatible with a systemic disease mediated by ANCA). The patient was started on intravenous methylprednisolone for 3 days and prednisone 50 mg daily thereafter along with azathioprine 50 mg twice daily. Serum creatinine trended down to 2.01 mg/dL 2 weeks after treatment initiation. Urine protein/creatinine ratio also trended down to 862 mg/g. In a follow-up visit to the clinic 3 months after initial presentation, the patient reported a better functional status. The lower extremity edema completely resolved. Serum creatinine was 1.23 mg/dL in the 3- month follow-up visit. Although there is no recommendation to randomly check serum creatinine in COVID-19 patients or those recently vaccinated, an elevated serum creatinine or abnormal urinalysis in this population warrants further investigation keeping in mind a possible autoimmune process. In conclusion, COVID-19 vaccines have substantial benefits. Rarely, autoimmune processes have been described post-vaccination. AAV is an example of an autoimmune disease that can be induced or flared up from a silent state by COVID-19 vaccines. A high index of suspicion regarding the presence of an autoimmune renal process is needed whenever a recently COVID-19-vaccinated individual presents for acute kidney injury.; Sender's Comments: As there is limited information in the case provided, the causal association between the reported events and the suspect drug cannot be excluded. The case will be reassessed once new information is available.   The impact of this report on the benefit/risk profile of the Pfizer drug 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.