Humoral Immune Response to COVID-19 Vaccination in Hemodialysis Patients: A Retrospective, Observational Case–Control Pilot Study

Introduction: Coronavirus 2 disease is associated with increased mortality and morbidity in chronic hemodialysis patients Methods: A retrospective, observational case–control pilot study was conducted on consecutive hemodialysis outpatients (cases) and control group of individuals with preserved renal function. Complete SARS-CoV-2 vaccination with BNT162b2 mRNA vaccine, followed by determination of serum antibodies after the second dose, were required from participants in both groups. Previous COVID-19 was an exclusion criterium. Results: 21 hemodialysis patients (M:F = 13:8, mean age 67.5 ± 13.4) and 16 controls without chronic kidney disease (M:F = 4:12, mean age 46.8 ± 12.7) were included. Hemodialysis patients had lower mean titers of serum antibodies to the SARS-CoV-2 spike antigen compared with controls (492.39 vs 1901.20 IU/mL, respectively; p < 0.001), a finding that was confirmed in the age-matched analysis on 18 participants (580.8 vs 1836.4 IU/mL, p = 0.006). Conclusions: This study supports the finding of hyporesponsiveness to mRNA vaccination among hemodialysis patients.