Introduction: Kidney transplant is associated with improved long-term outcomes and quality of life in children with end stage kidney disease requiring kidney replacement therapy (KRT). However, immunosuppression (IS) to prevent acute rejection increases the risk of severe infections for paediatric kidney transplant recipients (pKTR). There was a significant mortality risk for adult dialysis and transplant recipients during the COVID-19 pandemic. However, there was growing evidence that childhood populations mainly suffered with mildly symptomatic or asymptomatic COVID-19 infection. Few data are available in regards of clinical outcomes of immunosuppressed children, especially pKTR.
Objective: To appraise clinical outcomes of pKTR who experienced severe COVID-19 infection.
Methods: Using the CERTAIN Registry database participating centers, we surveyed paediatric nephrologists in Europe on the clinical outcomes of pKTR admitted to hospital during proven COVID-19 infection with positive SARS-CoV-2 PCR RNA.
Results: Twenty-one pKTR were admitted due to COVID-19 illness between October 2020 and April 2024 and three patients admitted twice for a total of 24 admissions with 100% patient and graft survival rates (Table 1). Median age at admission was 12.8 (IQR 4.6 - 17.0) years and median time from transplant to admission was 1.08 (IQR 0.56 - 3.2) years. The main reason for admission was pyrexia of unknown origin (Table 1).

One patient had acute kidney injury (AKI) and no patient required KRT. Two patients (8%) required intensive and high dependency care admission. Non-invasive respiratory support was required during 25% of admissions, but no patient required invasive respiratory support. Median length of admission was 6.0 (IQR 3.75 - 8.25) days. Six patients (25%) had received at least one dose of vaccine prior to admission, no patient had received SARS-CoV-2 prophylaxis, and four patients were treated with Sotrovimab. Six admitted patients (25%) had their immunosuppression regimen reviewed (Table 2) with five of these being admitted for fever and / or dehydration. At the last available follow-up in the registry, no patient had clinical or biopsy evidence of acute rejection episodes during or following their admission for COVID-19 infection.

Conclusion: COVID-19 infection symptoms remained mild for most pKTR despite the requirement for hospital admission. Most common clinical presentation in this cohort was not respiratory symptoms, but rather fever of unknown origin.  No change in baseline immunosuppression was required for most of the patients. Rate of vaccination was low in this cohort. These results are aligned with what had been observed in the general childhood population.