C-ANCA associated vasculitis/influenza vaccine-associated ANCA vasculitis; Pauci-immune associated necrotizing/crescentic glomerulonephritis involving 35% of glomeruli; This literature case was received on 29-Aug-2022, reported by other healthcare professional and concerned a 48-year-old, male patient.  This case report described a link between influenza vaccination and anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis.  The patient's concurrent condition included chronic allergic rhinitis. The patient's concomitant medications were not reported. The patient's historical vaccines included influenza vaccines, received for two years (prior to onset of ANCA vasculitis), with onset of arthralgias for which he required short-term steroids.   On an unspecified date, the patient was vaccinated with influenza vaccine (brand not specified; dose, route of administration, anatomical location and indication: not reported). The batch number was not reported.  On an unspecified date, a week after receiving influenza vaccine, the patient developed C-ANCA associated vasculitis/influenza vaccine-associated ANCA vasculitis.   On an unspecified date, eight weeks after receiving the vaccine as reported, the patient presented with migrating oligoarthralgia, lower extremity paresthesia, rash, right leg motor deficit, right eye pain, fever, chills, and night sweats.   On an unspecified date, physical exam showed dactylitis, enthesitis, a flat pruritic petechial rash of the lower extremities. A trial of short-term steroids was provided. Symptoms recurred once steroids were titrated. Laboratory tests showed increasing creatinine from 1.0 to 3.0 mg/dL, protein: creatinine (P:Cr) ratio from 0.5 to 1.2 gram per day (g/day), positive rheumatoid factor (RF) was 32 (high), c-reactive protein (CRP) was 7.5 (high), erythrocyte sedimentation rate (ESR) was 42 ,(high) and proteinase 3 (PR-3) was over > 8.0 (high). Computerised tomography (CT) of thorax showed bilateral diffuse ground-glass patchy infiltrates and 2-4 mm solid nodules. Skin biopsies showed small and medium-size vasculitis. Renal biopsy showed a Pauci-immune associated necrotizing/crescentic glomerulonephritis involving 35 % of glomeruli. The patient was treated with Solu-Medrol (methylprednisolone sodium succinate) at a dose of 1000 mg, daily for three days, followed by prednisone at a dose of 80 mg, daily and with rituximab at a dose of 1000 mg at day one and at day 15, then 500 mg, every six months. Steroids were titrated down until discontinuation.   On an unspecified date, reported as currently, the patient's creatinine currently was at baseline 1.0 mg/dl and P:Cr was 334 mg/g.  In conclusion, the patient showed high levels of anti-PR3 with pauci-immune pattern. Pauci-immune typifies systemic small-vessel vasculitis may lead to renal failure or pulmonary hemorrhage, so this report intended to increase awareness of influenza vaccine-associated ANCA vasculitis as rapid detection and treatment lead to optimal outcomes.  The outcome of both events was not reported.  The reporter assessed the event of 'ANCA-associated vasculitis' as related to influenza vaccine, however for the event of 'Pauci-immune glomerulonephritis' did not provide a causality assessment.  The event of 'ANCA-associated vasculitis' and 'Pauci-immune glomerulonephritis' were considered to be medically significant by a Physician within Seqirus'  and Management Department, while all other events were assessed as non-serious.    This case is linked with cases 202204028 and 202204360 (the same patient and literature article).  Company comment: A 48-year-old, male patient was vaccinated with the suspect product influenza vaccine. As reported a week after vaccination, the patient developed C-ANCA associated vasculitis/influenza vaccine-associated ANCA vasculitis. Eight weeks after vaccination, the patient presented with migrating oligoarthralgia, lower extremity paresthesia, rash, right leg motor deficit, right eye pain, fever, chills, and night sweats. Skin biopsies showed small and medium-size vasculitis. Renal biopsy showed a Pauci-immune associated necrotizing/crescentic glomerulonephritis involving 35 % of glomeruli. Based on presented information and plausible time relationship, causality for the reported events is assessed as possibly related.; Sender's Comments: A 48-year-old, male patient was vaccinated with the suspect product influenza vaccine. As reported a week after vaccination, the patient developed C-ANCA associated vasculitis/influenza vaccine-associated ANCA vasculitis. Eight weeks after vaccination, the patient presented with migrating oligoarthralgia, lower extremity paresthesia, rash, right leg motor deficit, right eye pain, fever, chills, and night sweats. Skin biopsies showed small and medium-size vasculitis. Renal biopsy showed a Pauci-immune associated necrotizing/crescentic glomerulonephritis involving 35 % of glomeruli. Based on presented information and plausible time relationship, causality for the reported events is assessed as possibly related.