Real-Life Prevention of Breakthrough SARS-CoV-2 Infections by mRNA Vaccines in Kidney Transplant Recipients vs Hemodialysis Patients

ABSTRACT

Purpose: The increased COVID-19 severity observed in kidney transplant recipients (KTR) has been widely reported. In addition, several studies have shown a reduced humoral and cellular response after mRNA vaccination in this population compared to hemodialysis patients. However, there is currently no information on real-life clinical protection (deaths and hospitalizations), a gap that this study aims to fill. Method(s) Observational prospective study. A total population of 1336 KTR and hemodialysis patients from three dialysis units affiliated to Hospital Clinic of Barcelona, Spain, vaccinated with two doses of mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 mRNA vaccines. The outcomes measured were SARS-CoV-2 infection diagnosed by a positive RT-PCR fourteen days after the second vaccine dose, hospital admissions derived from infection, and a severe COVID-19 composite outcome, defined as either ICU admission, invasive and non-invasive mechanical ventilation, or death. Result(s) Six per cent (18/302) of patients on hemodialysis were infected, of whom four required hospital admission (1.3%), only one (0.3%) had severe COVID-19, and none of them died. In contrast, 4.3% (44/1034) of KTR were infected, and presented more hospital admissions (26 patients, 2.5%), severe COVID-19 (11 patients, 1.1%) or death (4 patients, 0.4%). There were no correlations on the multivariate analysis between measured outcomes and baseline characteristics nor immunosuppressive treatment. Conclusion(s) The study highlights the need for further booster doses in KTR. In contrast, the hemodialysis population appears to have an adequate clinical response to vaccination, at least up to four months from its administration.