#2606 SARS-COV-2 ANTIBODIES IN PATIENTS ON HEMODIALYSIS AFTER THE MRNA VACCINATION
Authors: Taira Takayasu 
Published: June 2023

Abstract

Background and Aims
Strategies to minimize the transmission risk of the coronavirus disease 2019 (COVID-19) in patients on hemodialysis (HD) have been implemented worldwide. We investigated the levels of SARS-CoV-2 neutralizing antibodies in Japanese patients.

Method
Study (1) We measured the SARS-CoV-2 nucleocapsid antibodies in the serum samples of 55 patients who had undergone HD between August 1 and December 14, 2020. We included 42 patients who had two doses of the mRNA vaccine BNT162b2 between August 1 and November 30, 2021. We measured the levels of SARS-CoV-2 spike antibodies in their plasma and the SARS-CoV-2 nucleocapsid antibodies. We included 33 patients who had three doses of the mRNA vaccine, BNT162b2, between April 1st and July 30th, 2022. We measured the levels of SARS-CoV-2 spike antibodies in their plasma and the SARS-CoV-2 nucleocapsid antibodies. Study (2) We tested the serum samples of 8,982 Japanese adults with normal renal function for SARS-CoV-2 nucleocapsid antibodies between July 1 and November 18, 2020 as the control group. We tested 10 adults who had two doses of the mRNA vaccine BNT162b2, for SARS-CoV-2 spike antibodies at 4, 8, 12, 16, and 20 weeks after vaccination between May 1 and November 30, 2021.

Results
Two of 55 patients on HD were positive for SARS-CoV-2 nucleocapsid antibodies, while 54 were asymptomatic. One had SARS-CoV-2 nucleocapsid antibodies. The seropositivity of SARS-CoV-2 nucleocapsid antibodies was negative in 42 patients after the second dose of the BNT162b2 mRNA vaccine. No patients were infected with COVID-19. Of the 42 patients, 41 tested positive for SARS-CoV-2 spike antibodies after the second dose. The median titer of SARS-CoV-2 spike antibodies after vaccination was 253.5 (0.4-5,116) U/mL. All 33 HD patients tested positive for SARS-CoV-2 spike antibodies after the third dose. The mean titer of SARS-CoV-2 spike antibodies after the third vaccination was significantly higher than after the second BNT162b2 vaccination (N = 33: 9,745 U/mL vs, 221 U/mL, respectively; p&lt;0.0001). The mean SARS-CoV-2 spike antibodies titer of patients aged 56–92 years (266.7 U/mL) was lower than of patients aged 28–53 years (1,320.4 U/mL). The seropositivity of SARS-CoV-2 nucleocapsid antibodies was negative after the BNT162b2 mRNA vaccine. No patients were infected with COVID-19. Study (2) Serological testing showed that 47 of the 8,982 Japanese adults with normal renal function tested positive for SARS-CoV-2 nucleocapsid antibodies. The prevalence was significantly higher in the Japanese HD population than in adults with normal renal function (p&lt;0.01). The mean SARS-CoV-2 spike antibodies in the older group (55-73 years) were 1006, 643, 520, 464, and 390 U/mL at 4, 8, 12, 16 and 20 weeks post-vaccination. Contrastingly, the mean SARS-CoV-2 spike antibodies the younger group (26-45 years) were 2685, 2032, 1731, 1609, and 1527 U/mL at 4, 8, 12, 16, and 20 weeks post-vaccination.

Conclusion
Japanese HD patients had SARS-CoV-2 neutralizing capacities after the BNT162b2 vaccination. Most developed spike antibodies after the three doses. The mean titer of spike antibodies after the third vaccination was significantly higher than after the second vaccination (p&lt;0.0001).