COVID-19 Outcomes in Kidney Transplant Recipients in a German Transplant Center

Kidney transplant recipients (KTR) show higher morbidity and mortality from COVID-19 than the general population and have an impaired response to vaccination. We analyzed COVID-19 incidence and clinical outcomes in a single-center cohort of approximately 2500 KTR. Between February 1, 2020 and July 1, 2022, 578 KTR were infected with SARS-CoV-2, with 25 (4%) recurrent infections. 208 KTR (36%) were hospitalized, and 39 (7%) died. Among vaccinated patients, infection with the Omicron variant had a mortality of 2%. Unvaccinated patients infected with the Omicron variant showed mortality (9% vs. 11%) and morbidity (hospitalization 52% vs. 54%, ICU-admission 12% vs. 18%) comparable to the pre-Omicron era. Multivariable analysis revealed, being unvaccinated (OR = 2.15, 95% CI [1.38, 3.35]), infection in the pre-Omicron era (OR = 3.06, 95% CI [1.92, 4.87]), and higher patient age (OR = 1.04, 95% CI [1.03, 1.06]) are independent risk factors for COVID-19 hospitalization, whereas steroid-free immunosuppressive regimen was found to reduce the risk of COVID-19 hospitalization (OR = 0.51, 95% CI [0.33, 0.79]). This suggests that both, virological changes in the Omicron variant and vaccination, reduce the risk for morbidity and mortality from COVID-19 in KTR. Our data extend the knowledge from the general population to KTR and provide important insights into outcome during the Omicron era.