• epidemiology
• nephrology

As Munro and Faust point out, there appears a stark contrast in the case and mortality rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among children compared with the adult population.1 Whether infection in children is generally mild or asymptomatic, which goes undetected, or children are less susceptible to contracting the infection is unclear until screening programmes are introduced. What also remains uncertain is the risk of severe infection for children with significant underlying health concerns, including those with chronic kidney disease (CKD). The few studies reported have so far shown reassuringly low numbers and complication rates in children with coexisting diseases such as cancer and liver transplant recipients.2 3 The NHS England COVID-19 service evaluation (https://www.rcpch.ac.uk/resources/covid-19-service-evaluation-audit-care-needs-children-admitted-hospital-england), to date, has identified 220 confirmed cases in England of whom 44.4% of cases have coexisting disease; two children are reported to have CKD.

At the UK Renal Registry (UKRR) and in collaboration with the British Association for Paediatric Nephrology (BAPN), we have established an ongoing weekly COVID-19 surveillance system specifically for children with CKD. Lead clinicians from all 13 UK paediatric nephrology centres are asked to actively report cases with a confirmed positive COVID-19 antigen test result: data including NHS number, date of birth and whether the child is on kidney replacement therapy (KRT: dialysis or kidney transplant) are requested. Leads also inform the UKRR if no cases are identified. Data are checked and validated, with the NHS Demographics Batch Service used to capture the date of death for patients in England and Wales, the devolved nations for which this service is available. The UKRR is part of the Renal Association and collects, reports and analyses high-quality clinical data on children and adults with CKD. A legal basis to collect and analyse data is provided under section 251 support for research and audit.

Between 26 March and 15 July 2020, five UK children with CKD who tested positive for SARS-CoV-2 infection were reported; none have died. Cases were identified across the UK and included children with stage IV CKD and stage V requiring KRT. The majority (4/5) were male, with a median age of 11 years (IQR 8–12 years). While such low numbers preclude further analysis of risk factors, these data support the observation that infection in children with chronic coexisting disease is fortunately uncommon. It is likely that this figure represents children unwell enough to attend hospital for testing; however, it is encouraging that none have experienced adverse outcomes to date. In addition to weekly surveillance reporting, linkage of UKRR data for prevalent children in England with advanced CKD (stages IV, V and on KRT) to Public Health England and Hospital Episode Statistics data in the near future will enable us to accurately determine infection prevalence rates as well as comprehensively review infection-related hospitalisation episodes.

In light of these findings, alongside those from international colleagues,4 the BAPN has relaxed shielding criteria for children with kidney disease, details of which can be found on the Renal Association website (https://renal.org/covid-19/). This work, along with emerging evidence from other specialties, has enabled the Royal College of Paediatrics and Child Health to revise recommendations5 which have since been adopted by the UK government.