Immunogenicity of SARS-CoV-2 Vaccine in Dialysis

Abstract

Background: Patients receiving maintenance dialysis represent a high risk, immune-compromised population with 15-25% COVID mortality rate who were unrepresented in clinical trials evaluated for mRNA vaccines' emergency use authorization.

Method: All patients receiving maintenance dialysis that 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. We report seroresponse based on levels of immunoglobulin-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike antigen (seropositive ≥2) using FDA-approved semi-quantitative chemiluminescent assay (ADVIA Centaur® XP/XPT COV2G).

Results: Among 186 dialysis patients from 32 clinics in 8 states tested 23±8 days after receiving 2 vaccine doses, mean age was 68±12 years, with 47% women, 21% Black, 26% residents in long-term care facilities and 97% undergoing in-center hemodialysis. Overall seropositive rate was 165/186 (88.7%) with 70% at maximum titer and with no significant difference in seropositivity between BNT162b2/Pfizer (N=148) and mRNA-1273/Moderna (N=18) vaccines (88.1% vs. 94.4%, p=0.42). Among patients with COVID-19 history, seropositive rate was 38/38 (100%) with 97% at maximum titer.

Conclusion: Most patients receiving maintenance dialysis were seropositive after two doses of BNT162b2/Pfizer or mRNA-1273/Moderna vaccine. Early evidence suggests that vaccinated dialysis patients with prior COVID-19 develop robust antibody response. These results support an equitable and aggressive vaccination strategy for eligible dialysis patients, regardless of age, sex, race, ethnicity, or disability, to prevent the extremely high morbidity and mortality associated with COVID-19 in this high risk population.

Significance: In this retrospective observational evaluation of SARS-CoV-2 mRNA vaccine response defined by detectable levels of immunoglobulin-G against the receptor binding domain of the S1 subunit of SARS-CoV-2 spike antigen of ≥2 in serum of patients receiving maintenance dialysis, 165/186 (88.7%) were found to be seropositive (with 70% at maximum titer) at least 14 days after completing the second dose. No significant differences were observed by race or other subgroup or by vaccine manufacturer. Therefore, an equitable and aggressive vaccination strategy for all eligible maintenance dialysis patients, regardless of age, sex, race, ethnicity, or disability, is warranted to prevent the extremely high morbidity and mortality associated with COVID-19 in this high risk population.