ABSTRACT
Objective: A new generation of vaccine technology platform has been developed to combat the COVID- 19 pandemic, the mRNA vaccine. The EMA granted the Pfizer- BioNTech COVID-19 vaccine an emergency use authorization in December 2020 with limited clinical experience, especially in the pediatric population. Method(s): Here, we present a case-report of a 17-yearold girl, who was vaccinated with the mRNA-COVID vaccine in October 2021, and developed a gross hematuria and proteinuria the day after the vaccination. Result(s): The patient presented at our outpatient clinic three days after the vaccination with new-onset hematuria and proteinuria. Up to this date, she had no former known medical conditions and the family history was negative regarding kidney diseases. We excluded nephrolithiasis, autoimmune glomerulonephritis and urinary tract infection as causes. The laboratory chemistry of the kidney was within normal range. The proteinuria dissolved spontaneously, and a microhematuria persisted. One day after the second dose of Cominarty in November 2021, the gross hematuria with proteinuria relapsed. A treatment with an ACE-inhibitor did not have any effect on the proteinuria. At this point, only a few casereports of patients with a comparable clinical course, especially from Japan, were published. In suspicion of a vaccine-triggered nephritis we started a prednisolon therapy which dissolved the proteinuria and induced a regression of the haematuria to a minimal stage. Conclusion(s): Within the last year, the medical community has gained more insights concerning mRNA vaccines. There is growing evidence, that mRNA vaccines can trigger de novo or relapse IgA nephropathy. But more systematic research and long-term evaluation is desirable to elucidate the underling pathophysiology as well as the influence on kidney survival of affected patients in the future. Furthermore, patient education should incorporate the risk of hematuria and proteinuria in children when applying mRNA vaccines.