National study on the risks of COVID-19 infection for paediatric kidney transplant recipients: a retrospective, cross-sectional study.

Introduction: During the COVID-19 pandemic, evidence emerged that immunosuppressed children were less affected by COVID-19 infections compared with immunosuppressed adults. The aim of our study was to investigate how COVID-19 infections affected paediatric kidney transplant recipients (pKTR) in the UK.

Methods: Questionnaires regarding COVID-19 infection data and care of pKTR during the COVID-19 pandemic were sent to all 13 UK paediatric nephrology centres examining asymptomatic and symptomatic pKTR with positive COVID-19 PCR testing from 1 April 2020 to 1 December 2021.

Results: 63 pKTR who were 3.1 (range 0.1-15) years post-transplantation had COVID-19 infection with positive SARS-CoV-2 PCR RNA. Classical COVID-19 symptoms were present in half of the patients; with atypical presentations including diarrhoea (13%) and lethargy (13%) also noted, while a third of patients were asymptomatic. Eighteen patients (28%) were hospitalised including five asymptomatic patients admitted for other reasons. No patients needed ventilation or intensive care admission, and one patient received supplemental oxygen. There was evidence of acute kidney injury (AKI) in 71% of patients, but no patients needed kidney replacement therapy with haemofiltration or dialysis.

Conclusion: We report 10.4% of the UK paediatric renal transplantation population had documented COVID-19 infections with positive SARS-CoV-2 PCR RNA with 28% of those affected requiring hospitalisation. The increased incidence of AKI, particularly after the first wave of the COVID-19 pandemic, was possibly due to increased testing. There was low morbidity and mortality compared with the adult population.