Anti-SARS-CoV-2 IgG antibody titer after BNT162b2 mRNA COVID-19 vaccination in Japanese patients who underwent renal replacement therapy, hemodialysis, peritoneal dialysis, and kidney transplantation

Abstract

Background: Coronavirus disease (COVID-19) vaccination is recommended for patients undergoing renal replacement therapy (RRT), including hemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KT). However, the difference in the immune response between RRT patients and healthy individuals after mRNA vaccines remains uncertain.

Methods: This retrospective observational study evaluated the anti-severe-acute-respiratory-syndrome-coronavirus-2 (anti-SARS-CoV-2) IgG antibody acquisition, titers and their changes, normal response rate (reaching titers of healthy individuals), factors associated with a normal response, and effectiveness of booster vaccination in Japanese RRT patients.

Results: Most HD and PD patients acquired anti-SARS-CoV-2 IgG antibodies after the second vaccination; however, their antibody titers and normal response rates (62-75%) were low compared with those of healthy subjects. Approximately 62% of KT recipients acquired antibodies, but the normal response rate was low (23%). Anti-SARS-CoV-2 IgG antibody waning occurred in the control, HD, and PD groups, while negative or very low titers remained in KT recipients. Third booster vaccination was effective in most HD and PD patients. However, the effect was mild in KT recipients - only 58% reached a normal response level. Multivariate logistic regression analyses demonstrated that younger age, higher serum albumin level, and RRT other than KT were significantly associated with a normal response after the second vaccination.

Conclusions: RRT patients, particularly KT recipients, exhibited poor vaccine responses. Booster vaccination would be beneficial for HD and PD patients; however, its effect in KT recipients was mild. Further COVID-19 vaccinations using the latest vaccine or alternative procedures should be considered in RRT patients.

Keywords: COVID-19; Hemodialysis; Kidney transplantation; Peritoneal dialysis; SARS-CoV-2; Vaccine.

Fig. 1

Study flow. A total of 204 patients and controls were enrolled. Of the 47 controls, 7 were excluded 6 months after the second vaccination. Fifteen of the 95 HD patients were excluded at 3 months, and 22 were excluded at 6 months after the second vaccination. Two of the 21 PD patients were excluded 6 months after the second vaccination. Two of the 41 KT recipients were excluded at 3 months, and 3 were excluded at 6 months after the second vaccination. The number of participants in each group (control, HD, PD, and KT) at 3 months was 47, 80, 21, and 39, respectively. The number of participants in each group (control, HD, PD, and KT) at 6 months was 40, 58, 19, and 37, respectively

Fig. 2

Anti-SARS-CoV-2 IgG antibody titers at 3 months and 6 months after the second vaccination in the control, HD, PD, and KT groups. Multiple comparisons were performed among the groups using the Mann–Whitney U test. In addition, the anti-SARS-CoV-2 IgG antibody titer was compared using the Wilcoxon signed-rank sum test between 3 months (3 M) and 6 months (6 M) in each group. * vs. control at each time point: *, p < 0.05, **, p < 0.01, ***, p < 0.001; # vs. 3 M titers of each group: #, p < 0.05, ## p < 0.01, ### p < 0.001; comparison among RRT groups (HD vs. PD, PD vs. KT, KT vs. HD) 3 months and 6 months after the second vaccination: HD vs. PD: A’’, p < 0.001, A’, p < 0.01, A, p < 0.05; PD vs. KT: B’’, p < 0.001, B’, p < 0.01, B, p < 0.05; HD vs. KT: C’’, P < 0.001, C’, p < 0.01, C, p < 0.05

Fig. 3

The effects of the third booster vaccination against insufficient/non-response patients. Changes in antibody titer after the third vaccination are indicated in patients with insufficient/non-response (n = HD 12, PD 2, KT 26). 1: 3 months after the second vaccination, 2: 6 months after the second vaccination, 3: 3 months after the third vaccination