IgA nephropathy flare-up; Gross hematuria; proteinuria; This literature-non-study case was reported in a literature article and describes the occurrence of IGA NEPHROPATHY (IgA nephropathy flare-up) in a 50-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.   LITERATURE REFERENCE: "A case of Gross hematuria and IgA nephropathy flare-up following SARS-CoV-2 vaccination. Kidney Int Rep.    The patient's past medical history included Proteinuria. Concurrent medical conditions included Hypertension and Kidney dysfunction.   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, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced IGA NEPHROPATHY (IgA nephropathy flare-up) (seriousness criterion medically significant), HAEMATURIA (Gross hematuria) and PROTEINURIA (proteinuria). At the time of the report, IGA NEPHROPATHY (IgA nephropathy flare-up) and HAEMATURIA (Gross hematuria) outcome was unknown and PROTEINURIA (proteinuria) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Biopsy kidney: positive (Positive) Owing to persistent kidney dysfunction, 3 months after second vaccine dose, patient 3 underwent a kidney biopsy, showing an active and chronic IgA nephropathy with 13% active crescents. On an unknown date, Blood creatinine: 1.17 Baseline value was 1.17, 1.54 At Presentation value was 1.54 and 1.24 Follow-up 1 month post second dose was -1.24. On an unknown date, Blood urine: 11 to 25 Baseline value was 11 to 25, greater than  50 At Presentation value was greater than  50 and 11 to 25 Follow-up 1 month post second dose was 11 to 25. On an unknown date, Urine protein/creatinine ratio: 2.40 Baseline value was 2.40, 3.56 At Presentation value was 3.56 and 2.20 Follow-up 1 month post second dose was 2.20.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered IGA NEPHROPATHY (IgA nephropathy flare-up), HAEMATURIA (Gross hematuria) and PROTEINURIA (proteinuria) to be possibly related.    No concomitant information were reported.  In this case, patients 3  with chronic kidney disease and mild proteinuria at baseline, who developed not only gross hematuria but also significant proteinuria and kidney function decline. As his kidney function and proteinuria showed improvement, patient 3 declined immunosuppressive therapy and was treated with angiotensin-converting enzyme inhibition and close follow-up. Follow-up 1 mo post second dose hematuria and proteinuria returned to baseline; Serum creatinine (SCr) improving but above baseline.  Company Comment: This case concerns a 50 year-old, male patient with a history of Hypertension, Renal impairment and Proteinuria, who experienced the serious unexpected event of IgA nephropathy. The event occurred after the second dose of mRNA-1273 vaccine, exact date not provided. The rechallenge was not applicable, as the event was reported exclusively after the second dose. The medical history, of Hypertension, Renal impairment and Proteinuria remain as confounders. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2021-387504, MOD-2021-387565, MOD-2021-387567 (Patient Link).; Sender's Comments: This case concerns a 50 year-old, male patient with a history of Hypertension, Renal impairment and Proteinuria, who experienced the serious unexpected event of IgA nephropathy. The event occurred after the second dose of mRNA-1273 vaccine, exact date not provided. The rechallenge was not applicable, as the event was reported exclusively after the second dose. The medical history, of Hypertension, Renal impairment and Proteinuria remain as confounders. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.