Impact of COVID-19 Infections among Kidney Transplant Recipients.

More than 2 years since the start of the COVID-19 pandemic, cases continue to climb despite global efforts at viral control.This is largely driven by the emergence of viral variants.][3] In Singapore, despite having a robust test-trace-isolate strategy since the start of the pandemic, and one of the highest vaccination rates in the world with more than 80% of our population being fully vaccinated, the Delta variant has managed to "break through" our control measures, causing an exponential increase in the number of COVID-19 cases since the start of September 2021. 4 In addition, as restrictions loosen for practical and economic reasons, it is inevitable that COVID-19 infections in the immunocompromised patients (including kidney transplant recipients) will increase.Prior to September 2021, there were no reported COVID-19 infections in kidney transplant recipients on our follow-up.However, within the first few weeks of lifting restrictions (1 September to 15 October 2021), 12 of our patients were infected.Among them, 10 were treated at Singapore General Hospital and are described in this report.We had existing approval by the ethics committee of the institution to evaluate longitudinal outcomes in kidney transplant.Patient demographics, clinical presentation and outcomes are described in Table 1 (also Table S1 of Supplementary Materials in the online version of this article).Their median age was 61.5 (range 52-65) years.Most patients acquired COVID-19 from the community-6 (60%) from close contacts (either household or social contacts), 1 (10%) nosocomial transmission, and 3 (30%) unlinked.Seven (70%) patients had received at least 2 doses of the Pfizer BNT162b2 vaccine, and only 2 (28.6%) of these 7 had a serological response.The median time to infection from the second dose of vaccine was 137 (39-164) days.Three (30%) patients were unvaccinated, 1 of whom had prior COVID-19 infection in India.Most patients (80%) developed mild to moderate infections; the 2 (20%) patients who developed severe