Immunogenicity of SARS-CoV-2 Vaccine in Dialysis

Background: Patients receiving maintenance dialysis represent a high-risk, immune-compromised population with 15%-25% COVID-19 mortality rate who were unrepresented in clinical trials of mRNA vaccines.

Methods: All patients receiving maintenance dialysis who received two doses of SARS-CoV-2 mRNA vaccines with antibody test results drawn ≥14 days after the second dose, as documented in the electronic health record through March 18, 2021, were included. Response was on the basis of levels of Ig-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike-antigen (seropositive ≥2 U/L) using an FDA-approved semiquantitative chemiluminescent assay (ADVIA Centaur XP/XPT COV2G).

Results: Among 186 patients on dialysis from 30 clinics in eight states tested 23±8 days after receiving two vaccine doses, there were 165 (88.7%) responders with 70% at maximum titer. There was no significant difference between BNT162b2/Pfizer (148 out of 168, 88.1%) and mRNA-1273/Moderna (17 out of 18, 94.4%), =0.42. All 38 patients with COVID-19 history were responders, with 97% at maximum titer. Among patients without COVID-19, 127 out of 148 (85.8%) were responders, comparable between BNT162b2/Pfizer (113 out of 133) and mRNA-1273/Moderna (14 out of 15) vaccines (85.0% versus 93.3%, =0.38).

Conclusions: Most patients receiving maintenance dialysis responded after two doses of BNT162b2/Pfizer or mRNA-1273/Moderna vaccine, suggesting the short-term development of antispike antibody is good, giving hope that most of these patients who are vulnerable, once immunized, will be protected from COVID-19. Longer-term evaluation is needed to determine antibody titer durability and if booster dose(s) are warranted. Further research to evaluate the approach to patients without a serologic response is needed, including benefits of additional dose(s) or administration of alternate options.