Transplantation Direct (Jan 2023)

Humoral Responses in the Omicron Era Following 3-Dose SARS-CoV-2 Vaccine Series in Kidney Transplant Recipients

  • Caitríona M. McEvoy, MB, BCh, PhD,
  • Queenie Hu, PhD,
  • Kento T. Abe, BSc,
  • Kevin Yau, MD,
  • Matthew J. Oliver, MD, MHS,
  • Adeera Levin, MD,
  • Anne-Claude Gingras, PhD,
  • Michelle A. Hladunewich, MD, MS,
  • Darren A. Yuen, MD, PhD

DOI
https://doi.org/10.1097/TXD.0000000000001401
Journal volume & issue
Vol. 9, no. 1
p. e1401

Abstract

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Background. Kidney transplant recipients (KTRs) have a diminished response to SARS-CoV-2 vaccination compared with immunocompetent individuals. Deeper understanding of antibody responses in KTRs following third-dose vaccination would enable identification of those who remain unprotected against Omicron. Methods. We profiled antibody responses in KTRs pre- and at 1 and 3 mo post-third-dose SARS-CoV-2 mRNA-based vaccine. Binding antibody levels were determined by ELISA. Neutralization against wild type, Beta, Delta, and Omicron (BA.1) variants was determined using a SARS-CoV-2 spike-pseudotyped lentivirus assay. Results. Forty-four KTRs were analyzed at 1 and 3 mo (n = 26) post-third dose. At 1 mo, the proportion of participants with a robust antibody response had increased significantly from baseline, but Omicron-specific neutralizing antibodies were detected in just 45% of KTRs. Median binding antibody levels declined at 3 mo, but the proportion of KTRs with a robust antibody response was unchanged; 38.5% KTRs maintained Omicron-specific neutralization at 3 mo. No clinical variables were significantly associated with Omicron-neutralizing antibodies, but antireceptor binding domain titers appeared to identify those with Omicron-specific neutralizing capacity. Conclusions. Over 50% of KTRs lack Omicron-specific neutralization capacity 1 mo post-third mRNA-vaccine dose. Antibody levels of responders were well preserved at 3 mo. Anti receptor binding domain antibody titers may identify patients with a detectable Omicron-neutralizing antibody response.