Impaired Immune Response to SARS-CoV-2 Vaccination in Dialysis Patients and in Kidney Transplant Recipients

Background Patients with kidney failure on dialysis or after renal transplantation have a high risk for severe COVID-19 infection, and vaccination against SARS-CoV-2 is the only expedient prophylaxis. Generally, immune responses are attenuated in patients with kidney failure, however, systematic analyses of immune responses to SARS-CoV-2 vaccination in patients on dialysis and in kidney transplant recipients (KTRs) are still needed. Methods In this prospective, multicentric cohort study, antibody responses to COVID-19 mRNA vaccines (BNT162b2 [BioNTech/Pfizer] or mRNA-1273 [Moderna]) were measured in 32 patients on dialysis and in 28 KTRs. SARS-CoV-2-specific antibodies and neutralization capacity were evaluated and compared with controls (n=78) of a similar age range. Results After the first vaccination, SARS-CoV-2-specific antibodies were nearly undetectable in patients withkidney failure. After the second vaccination, 93% of the controls and 88% of patients on dialysis but only 37% of KTRs developed SARSCoV-2-specific IgG above cutoff. Moreover, mean IgG levels were significantly lower in KTRs (54 +/- 93 BAU/ml) compared with patients on dialysis (503 +/- 481 BAU/ml; P < 0.01). Both KTRs and patients on dialysis had significantly lower IgG levels compared with controls (1992 +/- 2485 BAU/ml; P < 0.001 and P < 0.01, respectively). Importantly, compared with controls, neutralizing antibody titers were significantly lower in KTRs and patients on dialysis. After the second vaccination, 76% of KTRs did not show any neutralization capacity against SARS-CoV-2, suggesting impaired seroprotection. Conclusions Patients with kidney failure show a significantly weaker antibody response compared with controls. Most strikingly, only one out of four KTRs developed neutralizing antibodies against SARS-CoV-2 after two doses of vaccine. These data suggest that vaccination strategies need modification in KTRs and patients on dialysis.