The Impact of COVID-19 Disease on Liver Transplant Recipients. Evolution of Infection, Prevention and Treatment Throughout the Pandemic “Waves”

Liver transplant recipients (LTR) have been considered a population group vulnerable to COVID-19 disease as they are chronically immunosuppressed patients with frequent comorbidities. This study describes the course of SARS-CoV-2 disease from February 2020 to December 2023 along seven pandemic “waves". We carried out an observational study on a 307 COVID-19 cases cohort in LTR with the aim of evaluating the changes in the disease characteristics over time and determining the risk factors for severe COVID-19. Older age and serum creatinine ≥ 2 mg/dL were found to be risk factors for hospital admission and respiratory failure. Calcineurin inhibitors was a protective factor for death from COVID-19, hospitalization and respiratory failure. 100% of patients who died (N = 12) were on mycophenolate mofetil, which was a determinant for respiratory failure. Azathioprine was associated with admission to the Intensive Care Unit (ICU) and with invasive mechanical ventilation (IMV). Vaccination was a protective factor for hospitalization, respiratory failure and mortality. Severe COVID-19 rate was higher during the first five waves, with a peak of 57.14% and the highest mortality rate (21.43%), in the 4th wave. IMV and ICU admission rates did not show significant differences across the periods.