Predictors and Dynamics of the Humoral and Cellular Immune Response to SARS-CoV-2 mRNA Vaccines in Hemodialysis Patients: A Multicenter Observational Study

Background Preliminary evidence suggests patients on hemodialysis have a blunted early serological response to SARS-CoV-2 vaccination. Optimizing the vaccination strategy in this population requires a thorough understanding of predictors and dynamics of humoral and cellular immune responses to differentSARS-CoV-2 vaccines.Methods This prospective multicenter study of 543 patients on hemodialysis and 75 healthy volunteers evaluated the immune responses at 4 or 5 weeks and 8 or 9 weeks after administration of the BNT162b2or mRNA-1273 vaccine, respectively. We assessed antiSARS-CoV-2 spike antibodies and T cell responses by IFN-? secretion of peripheral blood lymphocytes upon SARS-CoV-2 glycoprotein stimulation (QuantiFERON assay) and evaluated potential predictors of the responses.Results Compared with healthy volunteers, patients on hemodialysis had an incomplete, delayed humoral immune response and a blunted cellular immune response. Geometric mean antibody titers at both timepoints were significantly greater in patients vaccinated with mRNA-1273 versus BNT162b2, and a larger proportion of them achieved the threshold of 4160 AU/ml, corresponding with high neutralizing antibody titers in vitro(53.6% versus 31.8% at 8 or 9 weeks, P < 0.0001). Patients vaccinated with mRNA-1273 versusBNT162b2 exhibited significantly greater median QuantiFERON responses at both time points, and a larger proportion achieved the threshold of 0.15 IU/ml (64.4% versus 46.9% at 8 or 9 weeks, P < 0.0001).Multivariate analysis identified COVID-19 experience, vaccine type, use of immunosuppressive drugs, serum albumin, lymphocyte count, hepatitis B vaccine nonresponder status, and dialysis vintage as independent predictors of the humoral and cellular responses. Conclusions The mRNA-1273 vaccine's greater immunogenicity may be related to its higher mRNA dose. This suggests a high-dose vaccine might improve the impaired immune response to SARS-CoV-2 vaccination in patients on hemodialysis.