MO837: Antibody Response to Mrna Covid-19 Vaccination in Haemodialysis Patients—A 7-Month Follow-Up

Abstract

BACKGROUND AND AIMS Haemodialysis (HD) patients have a great risk of severe infection from coronovirus 2(SARS-CoV-2). However, chronic kidney disease is often associated with immunodeficiency and other existing vaccines have reduced efficacy in HD patients [1]. Humoral immune response to SARS-CoV-2 vaccination in chronic HD patients was investigated during a period of 7 months. METHOD A total of 39 patients, M/F = 34/5, aged 71 (47–90) years, dialyzed for 55(18–286) months, vaccinated with mRNA Comirnaty vaccine (BNT 162b2; BioNTech & Pfizer) were studied. Patients received two initial vaccine doses in March and April 2021, respectively, and 24 out of 39 patients received a third dose in October 2021. We analyzed the antibody response to the spike (S) antigen of SARS-CoV-2 at 0, 1, 4 and 7 months (November) after second vaccine dose in all patients. We also compared serum antibody titers at time-point 7 between the 24/39 patients and 20 healthy age-matched individuals, also vaccinated with three doses at the same months. RESULTS At time-point 0, titers of S protein-targeting antibodies(S-Abs) were 5 ± 1 AU/mL. At 1 month S-Abs were < 50 AU/mL in 2 patients (5.15%), between 51 and 100 AU/mL in 2/39 patients (5.15%), between 101 and 1000(528 ± 292) AU/mL in 19/39 patients (48.7%) and between 1001 and 10 000 (4486 ± 2547) AU/mL in 13/39 patients(33.3%). S-Abs were higher than 10 000(14 516 ± 3062) AU/mL in 3/39 patients (7.7%) after previous infection. In the 36/39 patients not infected, at 4 months there was a significant titer decrease compared with values at 1 month: from 3108 ± 4361 to 1442 ± 4357 AU/mL; P < 0.001. At 7 months, the 24/39 patients vaccinated with the third dose showed increased titers in comparison with values at 1 and 4 months, respectively (9285 ± 11 202 versus 1957 ± 2763 AU/mL; P < 0.001 and versus 584 ± 669 AU/mL; P < 0.001, respectively). Among 15/39 patients who did not receive the third dose, 4/15 with an average titer of 739 AU/mL died from other causes, 3/15 with an average titer of 25 468 AU/mL were hospitalized for COVID-19 and discharged and 8/15 showed further titer decrease (2117 ± 4887 to 950 ± 1855 AU/mL; P = 0.031). After the third dose higher S-Abs were observed in healthy controls compared with HD patients (18 050 ± 15 374 versus 9285 ± 11 202 AU/mL; P = 0.032). CONCLUSION Healthy controls showed a better humoral immune response compared with patients. Two doses of mRNA BNT162b2 vaccine induced an initial satisfactory humoral response in HD patients but S-Abs significantly declined subsequently [2]. Humoral response was significantly better after the third dose and booster immunization seems necessary [3].