Early Humoral Responses of Hemodialysis Patients after COVID-19 Vaccination with BNT162b2.

Abstract

Background and objectives Patients receiving hemodialysis are at high risk for both SARS-CoV-2 infection and severe COVID-19 disease. A life-saving vaccine is available, but sensitivity to vaccines is generally lower in dialysis patients. Little is yet known about antibody responses after COVID-19 vaccination in this vulnerable group. Design, setting, participants, and measurements In this prospective single-center study, we included 22 dialysis patients and 46 healthy controls from Heidelberg University Hospital between December 2020 and February 2021. We measured anti-S1 IgG with a threshold index for detection >1, neutralizing antibodies with a threshold for viral neutralization of ≥30% and antibodies against different SARS-CoV-2 fragments 17-22 days after the first and 18-22 days after the second dose of the mRNA vaccine BNT162b2. Results After the first vaccine dose, 4/22 (18%) dialysis patients compared with 43/46 (93%) healthy controls developed positive anti-S1 IgG, with a median (IQR) anti-S1 IgG index of 0.2 (0.1-0.7) compared with 9 (4-16), respectively. SARS-CoV-2 neutralizing antibodies exceeded the threshold for neutralization in 4/22 (18%) dialysis patients compared with 43/46 (93%) in healthy controls, with a median (IQR) percent inhibition of 11 (3-24) compared with 65 (49-75), respectively. After the second dose, 14/17 (82%) of dialysis patients developed neutralizing antibodies exceeding the threshold for viral neutralization and antibodies against the receptor-binding S1-domain of the spike protein, compared to 46/46 (100%) of healthy controls, respectively. The median (IQR) percent inhibition was 51 (32-86) compared to 98 (97-98) in healthy controls. Conclusions Patients receiving long-term hemodialysis show a reduced antibody response to the first and second doses of the mRNA vaccine BNT162b2. The majority (82%) develop neutralizing antibodies after the second dose, but at lower levels than healthy controls.