Changes in Spike Protein Antibody Titer Over 90 Days after the Second Dose of SARS- CoV-2 Vaccine in Japanese Dialysis Patients

Abstract

Objectives There is no report on antibody titers after vaccination against SARS-CoV-2 in Japanese dialysis patients. As dialysis is different between Japan and other countries, changes in antibody titers were examined. Methods Baseline characteristics and anti-spike protein antibody titers (Roche) over 90 days after administration of the BNT162b2 messenger RNA vaccine were investigated in dialysis patients. Results The maximum anti-spike protein antibody titer after the second dose was 737.9 (326.8 to 1143.4) and was reached at 19 (17 to 24.3) days after the second dose. Antibody titers decreased over time, with titers of 770 (316.4 to 1089) at 15 days, 385 (203 to 689.7) at 30 days, 253.5 (138 to 423) at 60 days, and 208 (107 to 375) at 90 days after the second dose. When an antibody titer of 137.052 U/mL was assumed to be a measure related to breakthrough infection, the proportion of subjects with antibody titers exceeding this level was 90.1％ at 15 days, 85.3% at 30 days, 75.0% at 60 days, and 65.4% at 90 days after the second dose. When a decrease in antibody titers below the assumed breakthrough level was defined as an event, subjects with a pre-dialysis albumin ≥ 3.5 were significantly less likely to experience an event than subjects with a pre-dialysis albumin < 3.5. In addition, this study suggests that the presence of anti-spike protein levels ≥ 313 at 30 days after the second vaccine dose might be a factor in maintaining antibody titers exceeding the assumed breakthrough level at 90 days after the second dose. Conclusions The maximum antibody titers and the antibody titers at 90 days after the second vaccine dose in Japanese dialysis patients were approximately 30% of those in non-dialysis individuals reported otherwise, it was similar to those in dialysis patients in other countries. Whether an additional vaccine dose is needed should be determined based on indicators serving as factors in maintaining antibody titers as well as the status of the spread of infection.