Immunogenicity of the BNT162b2 Vaccine in Patients Undergoing Maintenance Hemodialysis Is Associated with Medical Conditions

Background and Objectives: Patients undergoing maintenance hemodialysis have an attenuated immune response to vaccination. The aim of our study was to determine the predictive factors for humoral response to vaccination with the BNT162b2 mRNA vaccine (Pfizer-BioNTech) in patients on maintenance hemodialysis. Design, Setting, Participants, and Measurements: In this retrospective, single-center study, we included patients on maintenance hemodialysis already vaccinated with two doses of the BNT162b2 vaccine (Pfizer-BioNTech) and with a post-vaccination serological follow-up. Results: 252 patients were included for study with a mean age of 71.9 (±14.4) years. Twelve patients (4.7%) were under immunosuppressive therapy (calcineurin inhibitors: n = 4; chemotherapy for myeloma: n = 3; last infusion of rituximab over the previous 4 years: n = 2; abatacept: n = 2; adalimumab n = 1). Three of these patients were under immunosuppressive therapy for nonrenal solid organ transplantation. Multivariate analysis identified immunosuppressive therapy (OR 4.73 [1.38–16.17], p = 0.013) and lower baseline albumin levels (OR 1.23 [1.09–1.38], p < 0.001) as independent predictive factors of nonresponse to vaccination. Older age (β = −0.59 ± 0.21, p = 0.006) and immunosuppressive therapy (β = 40.33 ± 13.33, p = 0.003) were significantly associated with lower humoral response to vaccination. Conclusions: Approximately 90% of patients under maintenance hemodialysis developed specific antibodies to the BNT162b2 mRNA vaccine. Immunosuppressive therapy, malnutrition, and older age were associated with a higher risk of nonseroconversion or lower humoral response to mRNA-based vaccination against SARS-CoV-2. We strongly recommend serological monitoring after vaccination to determine booster timing, especially for patients with malnutrition or on immunosuppressive therapy.