This literature-non-study case was reported in a literature article and describes the occurrence of GLOMERULONEPHRITIS RAPIDLY PROGRESSIVE (Anca-associated glomerulonephritis), PYREXIA (Fevers), HEADACHE (intermittent headaches) and MICROSCOPIC POLYANGIITIS (Positive p-ANCA and hightiter myeloperioxidase antibody confirming the diagnosis of Microscopic polyangitis) in a 63-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     The patient's past medical history included Latent tuberculosis. Concurrent medical conditions included Hypertension, Chronic obstructive pulmonary disease and Giant cell arteritis.    On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced GLOMERULONEPHRITIS RAPIDLY PROGRESSIVE (Anca-associated glomerulonephritis) (seriousness criteria hospitalization and medically significant). an unknown date, the patient experienced PYREXIA (Fevers) (seriousness criterion hospitalization), HEADACHE (intermittent headaches) (seriousness criterion hospitalization) and MICROSCOPIC POLYANGIITIS (Positive p-ANCA and hightiter myeloperioxidase antibody confirming the diagnosis of Microscopic polyangitis) (seriousness criteria hospitalization prolonged and medically significant). The patient was treated with PREDNISONE ACETATE (oral) for Glomerulonephritis, at an unspecified dose and frequency; RITUXIMAB (intravenous) for Glomerulonephritis, at an unspecified dose and frequency and METHYLPREDNISOLONE SODIUM SUCCINATE (SOLUMEDROL) (intravenous) for Glomerulonephritis, at a dose of given for 3 days. At the time of the report, GLOMERULONEPHRITIS RAPIDLY PROGRESSIVE (Anca-associated glomerulonephritis) and MICROSCOPIC POLYANGIITIS (Positive p-ANCA and hightiter myeloperioxidase antibody confirming the diagnosis of Microscopic polyangitis) was resolving and PYREXIA (Fevers) and HEADACHE (intermittent headaches) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Biopsy kidney: abnormal showed Pauci-immune, necrotizing, crescentic glomerulonephritis and small vessel vasculitis. On an unknown date, Blood creatine: 2.2 mg/dl 2.2 mg/dL, 1.8 mg/dl One week post-biopsy serum creatinine was 1.8 mg/dL. and 1.4 mg/dl 1.4 mg/dL. On an unknown date, C-reactive protein: elevated (High) 105 mg/L and elevated (High) 119 mm/hr. On an unknown date, Physical examination: unremarkable unremarkable. On an unknown date, Red blood cell sedimentation rate increased: elevated 119 mm/hr. On an unknown date, Serology test: positive positive p-ANCA and high titer myeloperoxidase antibody, confirming the diagnosis of Microscopic polyangiitis (MPA). On an unknown date, Urine analysis: hematuria and proteinuria noted new-onset microscopic hematuria and proteinuria (1.5 g/24 hr).     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered GLOMERULONEPHRITIS RAPIDLY PROGRESSIVE (Anca-associated glomerulonephritis), PYREXIA (Fevers), HEADACHE (intermittent headaches) and MICROSCOPIC POLYANGIITIS (Positive p-ANCA and hightiter myeloperioxidase antibody confirming the diagnosis of Microscopic polyangitis) to be possibly related.    On admission, the patient was afebrile with normal vitals and unremarkable physical examination. Patient noted his GCA had been in remission off treatment for two years.  Concomitant medications were not reported.  Company Comment: This case concerns a 63-year-old male patient with a relevant medical history of biopsy proven Giant cell arteritis, who experienced the unexpected serious events of Glomerulonephritis rapidly progressive and Microscopic polyangiitis after mRNA- 1273 Moderna vaccine (Moderna COVID-19 Vaccine). The onset of the events occurred approximately 3 weeks after the second dose of mRNA- 1273 vaccine. Clinical manifestations included pyrexia and headache. Laboratory results showed microhematuria, proteinuria, acute kidney injury and positive p-ANCA and myeloperoxidase antibody. Sedimentation rate and C-reactive protein were elevated. Renal biopsy showed  pauciimmune, necrotizing, crescentic glomerulonephritis and small vessel vasculitis. Treatment with solumedrol,  rituximab and prednisone was given, with improvement of renal function. The rechallenge is not applicable, since the event was reported exclusively after the second dose. Previous Gian cell vasculitis remains a confounder. The benefit-risk relationship of mRNA- 1273 vaccine / Moderna COVID-19 Vaccine is not affected by this report; Sender's Comments: This case concerns a 63-year-old male patient with a relevant medical history of biopsy proven Giant cell arteritis, who experienced the unexpected serious events of Glomerulonephritis rapidly progressive and Microscopic polyangiitis after mRNA- 1273 Moderna vaccine (Moderna COVID-19 Vaccine). The onset of the events occurred approximately 3 weeks after the second dose of mRNA- 1273 vaccine. Clinical manifestations included pyrexia and headache. Laboratory results showed microhematuria, proteinuria, acute kidney injury and positive p-ANCA and myeloperoxidase antibody. Sedimentation rate and C-reactive protein were elevated. Renal biopsy showed  pauciimmune, necrotizing, crescentic glomerulonephritis and small vessel vasculitis. Treatment with solumedrol,  rituximab and prednisone was given, with improvement of renal function. The rechallenge is not applicable, since the event was reported exclusively after the second dose. Previous Gian cell vasculitis remains a confounder. The benefit-risk relationship of mRNA- 1273 vaccine / Moderna COVID-19 Vaccine is not affected by this report