This is a Literature report from Kidney International, 2021, Vol 100 (1), Pgs 238, entitled "A case of gross hematuria and IgA nephropathy flare-up following SARS-CoV-2 vaccination". A 52-years-old female patient received second dose of bnt162b2 (PFIZER-BINTECH COVID-19 mRNA VACCINE, Solution for injection, Batch/Lot number was not reported), via an unspecified route of administration on an unspecified date as DOSE 2, SINGLE for COVID-19 immunization. Medical history included iga nephropathy from 2017 to an unknown date, URI from 01Apr2019 to an unknown date following shingles vaccine, Vasculitis flare-ups following vaccinations have been reported in the past. Concomitant medication included lisinopril (LISINOPRIL) taken for an unspecified indication. The patient previously received first dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Batch/Lot number was not reported), via an unspecified route of administration on an unspecified date as DOSE 1, SINGLE for covid-19 immunisation and experienced no adverse event, first dose, developed no symptom. The patient previously received Shingrix vaccine and experienced gross hematuria, exacerbations since diagnosis, following the first shot. The patient previously received influenza vaccination annual, no symptoms. On an unspecified date, the patient experienced delayed-type hypersensitivity reaction, gross hematuria, iga nephropathy flare, fever, myalgias, body aches, lower back pain bilaterally. Patient developed gross hematuria within 24 hours of receiving a second dose of the Pfizer vaccine. Table 1 summarizes clinical data. Her workup was notable for proteinuria of 4.2 g/g of creatinine with serum creatinine at baseline. Of note, SARS-CoV-2 antibody testing prior to vaccination was negative, and she developed no symptoms after the first vaccine dose. Repeated testing within 1 week demonstrated resolution of hematuria and improving proteinuria. Interestingly, she developed gross hematuria following the first shot of the Shingrix vaccine 2 years prior but no symptoms following annual influenza vaccinations. The IgA nephropathy flare in our patient following the second SARS-CoV-2 vaccine dose without known prior exposure to SARS-CoV-2 suggests it was mediated by a delayed-type hypersensitivity reaction. Patient symptoms improved within a week without any intervention aside from continued renin-angiotensin-aldosterone system blockade. It has been reported that severe coronavirus disease 2019 (COVID-19) illnesses can trigger an IgA response in the bronchial mucosa. However, it was unclear how a non mucosal vaccine triggers this response. Suggested that nephrologists closely follow their patients after COVID-19 vaccination to evaluate for varying degrees of flares, particularly after the second dose of an mRNA vaccine without prior exposure to SARS-CoV-2. Patient symptoms and details of workup: Hematuria 5 d after Pfizer second dose, Resolved. The patient underwent lab tests and procedures which included biopsy: proven iga nephropathy, baseline Cre: 0.7-0.8 g/dl, serum creatinine: at baseline, urine proteine: improving, RBCs in urine: yes, SARS-CoV-2 antibody testing: negative prior to vaccination, last urine microalbumin/Cre before exacerbation: baseline always less than 1000 mg/g, except exacerbations, 633.1 mg/g on unspecified date in 2020, Urine microalbumin/Cre 48 h after Pfizer second dose: 2411.3 mg/g, Urine microalbumin/Cre 5 d after Pfizer second dose: 1441 mg/g, urine protein/creatinine ratio: 4.2 g/g on unspecified date, gross hematuria: yes, resolution on unspecified date in 2020. Seriousness of delayed-type hypersensitivity reaction was medically significant. No treatment received for delayed-type hypersensitivity reaction and gross hematuria. The clinical outcome of gross hematuria was recovered on an unspecified date, delayed-type hypersensitivity reaction was recovering and other events were unknown.; Sender's Comments: Based on the information provided, known drug safety profile and plausible temporal association, the causality between BNT162B2 and the events hypersensitivity, hematuria and IgA nephropathy cannot be completely excluded. The impact of this report on the benefit-risk profile of the Pfizer product and on the conduct of the study 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.