Granulomatosis with polyangiitis; Pauci-immune glomerulonephritis; This is a literature report for the following literature source(s):   A 27-year-old with no pertinent prior medical or significant family history received his first dose of the Pfizer-BioNTech mRNA vaccine in late Sep2021 while overseas. Four days after vaccination, the patient reported polyarthralgias, fever, and diffuse myalgias to his primary doctor. These symptoms were attributed to general immunization side effects, and patient was sent home with acetaminophen. Three weeks later, the patient presented to the emergency department (ED) with persistent arthralgias, severe positional chest pain and dyspnea on exertion. Based on his symptoms and laboratory evidence, he was diagnosed clinically with pericarditis and discharged on colchicine and celecoxib. In the following 10 days, patient had two additional ED visits with worsening chest pain, dyspnea, resting tachycardia, and sinus pain with epistaxis, palpable purpuric rash on the lower extremities, gingival bleeding, and elevated C-reactive protein. He was started on a short burst of prednisone 40 mg which alleviated his symptoms; however, upon cessation, all symptoms returned. His severe symptoms rapidly returned upon cessation of steroids. The patient was restarted on high-dose oral prednisone and to transferred back to home country for higher level of care with rheumatology specialists for expedited workup of a rapidly progressive multi-system inflammatory pathology. Once transferred, an extensive workup was conducted including the laboratory data. Of note, chart review into the patient's prior history showed that his baseline serum creatinine values had been 0.8 to 1 mg/dl for years and that he had never previously showed any evidence of proteinuria or hematuria on past urinalyses. Computed tomography (CT) scan of the chest was performed and showed confluent centrilobular ground glass opacities which were thought to represent either atypical infection or mild alveolar hemorrhage. Transthoracic echocardiogram was performed but was unremarkable with only trace pericardial effusion seen. Bronchoscopy and nasoscopy were also conducted and demonstrated diffuse erythema and inflammation, but there was no direct evidence seen of diffuse alveolar hemorrhage and no biopsies were taken. While the patient's symptoms did improve with oral steroids, his proteinuria and microscopic hematuria persisted, prompting nephrology consultation and eventually, renal biopsy. Pathology from the biopsy demonstrated pauci-immune glomerulonephritis with early crescent formation, segmental fibrinoid necrosis, and mild acute tubular injury. Collective clinical, laboratory, and biopsy data were supportive of diagnosis of GPA with associated glomerulonephritis. After discharge, the patient was started on induction therapy with rituximab 1000 mg IV for 2 doses on day 0 and 15, oral prednisone taper, and losartan. Within 1 month of induction, his clinical symptoms resolved, hemoglobin trended back to baseline, and urine protein to creatinine ratio significantly improved by >50% to 910 to 360 mg/g. The patient underwent other laboratory tests and procedures: Antibody test (0.0-3.5): Low titers; >100 IU/ml, notes: High; Anti-glomerular basement membrane antibody (0-20): 3 iU; Antineutrophil cytoplasmic antibody (normal high range 1:20): <1:20; Antineutrophil cytoplasmic antibody (0-9): <9.0 IU/ml; <1:20; Antineutrophil cytoplasmic antibody decreased (normal high range 1:20): 1:320, notes: Low titers; Antinuclear antibody: Negative; Antiphospholipid antibodies (0-20): <9 iU; Blood albumin (3.5-5.2): 2.6 g/dl, notes: Low; Blood creatinine (0.7-1.2): 0.8 to 1; 1.22 mg/dl; Blood thyroid stimulating hormone (0.27-4.2): 0.22 uiU/mL; 0.22 uiU/mL; Brain natriuretic peptide (0-125): 55 pg/mL; Chlamydia test: Negative; Complement factor C3 (82-167): 102 mg/dl; Complement factor C4 (16-48): 15 mg/dl; C-reactive protein (normal high range 2.9): 6.2 mg/l, notes: Elevated; Cryoglobulins: None detected; Eosinophil count (0-0.45): 1.44, notes: Unit: 10*9/l; high; Haemoglobin (13-18): 10.7 g/dl; Trended back to baseline; Hepatitis B surface antigen: Negative; Hepatitis C core antibody: Non-reactive; Histone antibody (normal high range 1.0): 0.4; HIV test: Not detected; Neisseria test: Negative; Red blood cells urine (normal high range 5): 31-50, notes: Unit: /HPF; high; Rheumatoid factor (0-20): <10 IU/ml; SARS-CoV-2 test: Not detected; Thiopurine methyltransferase polymorphism (15-24): 24.2 IU/ml; Troponin I (0-0.015): <0.015 ng/ml; Urine protein/creatinine ratio: 909 mg/g, notes: High; 360 mg/g, notes: Improved by >50%. In the presented case, compelling evidence implies at least an association between the administration of the COVID-19 vaccine and the onset of his AAV symptoms. Of course, causation in this case cannot be proven, but the patient had previously had no significant past medical history, no family history of AAV or autoimmune disease, no prior GPA symptoms, and no hematuria or proteinuria on multiple urinalyses over several years prior to the vaccination. The likelihood of GPA spontaneously developing in a young, healthy 27-year-old within a 1-month time window after getting the vaccine but with no relation to the vaccination seems improbable at best. There does remain the possibility of underlying low titers of ANCAs and PR3 antibodies being present in the serum prior to the vaccination that then flared up in production and the associated vasculitis complications as a result of the inflammatory response to the vaccination, but the authors do not have any serologic data prior to the vaccination to prove or disprove this theory. Since the onset of the COVID-19 pandemic, there have been rare reports of COVID-19 infection and vaccination being associated with de novo development and flares of AAV diseases. The authors present another such case of a biopsy-proven GPA with pauci-immune glomerulonephritis occurring within about 6 weeks of receiving the Pfizer-BioNTech COVID-19 vaccination that responded well to immunosuppressive therapy. The exact mechanism by which this occurs is not known. As the pandemic continues into its third year, the authors hope that this case and other similar cases will lead to further understanding of COVID-19 and its relation to AAV disease.; Sender's Comments: Based on available information and temporal relationship, a possible causal relationship cannot be excluded between the suspect vaccine BNT162B2 and events granulomatosis with polyangiitis in this young man without any medical history which could provide alternative explanation. 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.