An adolescent presenting with IgA nephropathy and persistent decreased kidney function after COVID-19 vaccination during follow-up for asymptomatic hematuria: a clinicopathological study.

Although the coronavirus disease 2019 (COVID-19) vaccine has been proven to be effective and safe in most adults and children, various diseases, including IgA nephropathy, sometimes occur as an adverse effect. We herein describe a case of IgA nephropathy in a 16-year-old, male patient with persistent kidney dysfunction following COVID-19 vaccination and present the clinicopathological course of the disease. The patient presented to the outpatient clinic with a history of gross hematuria 6 days after receiving the COVID-19 vaccine. Prior to the current presentation, he was being examined regularly at an outpatient clinic for asymptomatic hematuria. His mother had received a diagnosis of IgA nephropathy, and his younger brother had received a diagnosis of asymptomatic hematuria. A blood test of this patient demonstrated elevated serum creatinine, and IgA nephropathy was pathologically diagnosed (Oxford classification M0E1S1T0C1). Prednisolone and immunosuppressants were administered promptly to treat the decreased kidney function and the pathology. Nevertheless, the failure of his kidney function to recover to the state it was in prior to this episode may have led to the formation of chronic lesions, causing irreversible kidney tissue damage. Some patients with IgA nephropathy, asymptomatic hematuria or a family history of kidney-related symptoms may experience kidney dysfunction after COVID-19 vaccination and require prednisolone or immunosuppressive therapy to stem the progressive deterioration of their kidney function. Prior to receiving the COVID-19 vaccine, patients with any of these conditions should be provided with an appropriate explanation of the risks and be asked for their consent to be vaccinated.