New-onset pediatric nephrotic syndrome following Pfizer-BioNTech SARS-CoV-2 vaccination: a case report and literature review.

Various new vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been rapidly developed. The new onset and recurrence of nephrotic syndrome triggered by some vaccines have been documented and several adult cases of minimal change nephrotic syndrome newly developing after SARS-CoV-2 vaccination have been reported. However, no reports of pediatric cases have been published. Indications for SARS-CoV-2 vaccines have been expanded to those as young as 12 years old and vaccination of children has just started in Japan. We encountered a 15-year-old boy without underlying disease who newly developed nephrotic syndrome after SARS-CoV-2 vaccination with BNT162b2 (Pfizer-BioNTech). He developed eyelid edema 4 days after vaccination and peripheral edema of the lower extremities a further 4 days later. Twenty-one days after vaccination, 60 mg of oral daily prednisolone was started. He achieved complete remission in 12 days without complications such as hypertension or acute kidney injury. We clinicians should be aware of the possibility of nephrotic syndrome developing after SARS-CoV-2 vaccination, not only in adults, but also in children.