Background: Kidney failure patients 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 kidney failure patients, however, systematic analyses of immune responses to SARS-CoV-2 vaccination in dialysis patients and in kidney transplant recipients (KTR) are still missing. Methods: In this prospective multicentric cohort study, antibody responses COVID-19 mRNA vaccines (BNT162b2; Biontech/Pfizer or mRNA-1273; Moderna) were measured in 32 dialysis patients and in 28 KTRs. SARS-CoV-2-specific antibodies and neutralization capacity were evaluated and compared to controls (n=78) in a similar age-range. Results: After the first vaccination, SARS-CoV-2-specific antibodies were nearly undetectable in kidney failure patients. After the second vaccination, 93% of the controls and 88% of dialysis patients but only 37% of KTRs developed SARS-CoV-2-specific IgG above cut-off. Moreover, mean IgG levels were significantly lower in KTRs (54±93 BAU/ml) compared to dialysis patients (503±481 BAU/ml, p<0.01). Both KTRs as well as dialysis patients had significantly lower IgG levels compared to controls (1992±2485 BAU/ml; p<0.001 and p<0.01). Importantly, compared to controls, neutralizing antibody titers were significantly lower in KTRs and dialysis patients. After the second vaccination, 76% of KTRs did not show any neutralization capacity against SARS-CoV-2 suggesting impaired seroprotection. Conclusions: Kidney failure patients show a significantly weaker antibody response compared to controls. Most strikingly, only one out four KTRs developed neutralizing antibodies against SARS-CoV-2 after two doses of vaccine. These data suggest that vaccination strategies need modification in immune transplant and dialysis patients.
SARS-CoV-2-specific Humoral Immune Responses after A Single Dose of Inactivated Whole-virus SARS-CoV-2 Vaccine in Kidney Transplant Recipients: An Initial Report
