Brazilian Journal of Nephrology · Published 2026-03-01 · DOI 10.1590/2175-8239-jbn-2025-0206en
Abstract Introduction: Dialysis patients and kidney transplant recipients (KTRs) present impaired immune response to COVID-19 vaccines. Although vaccination remains the primary strategy to reduce mortality, data on the cellular immune response kinetics in these populations are limited. This study evaluated the kinetics of vaccine-induced cellular immunity to SARS-CoV-2 in dialysis and KTRs without prior infection. Methods: This is a post-hoc analysis of a prospective, observational, single-center study comparing the cellular immunity kinetics induced by SARS-CoV-2 vaccination in adult patients undergoing kidney transplant (n = 77) and patients on dialysis (n = 92). Those who had COVID-19 were excluded. Blood samples were collected at screening and at 1, 3, 6, and 12 months to assess SARS-CoV-2-specific T-cell responses using a commercial Interferon-gamma release assay (IGRA, QuantiFERON SARS-CoV-2 RUO), with results classified as positive, negative, or indeterminate. Comparisons were performed using chi-square and Mann-Whitney tests. Results: Positive IGRA results were infrequent in transplant and dialysis patients over time (Screening: 8.1% vs. 23.2%; M1: 14.1% vs. 16.5%; M3: 10% vs. 7.1%; M6: 1.5% vs. 2.5%; M12: 15.2% vs. 13.4%), but indeterminate results were common (Screening: 82.4% vs. 17.8%; M1: 71.8% vs. 42.4%; M3: 62.9% vs. 47.1%; M6: 69.1% vs. 58.8%; M12: 30.3% vs. 19.4%), particularly among KTRs, although they received more vaccine boosters (95 vs. 63; p < 0.001). No correlation was observed between the number of vaccine doses and IGRA positivity. Conclusion: Despite multiple vaccine boosters, dialysis and kidney transplant patients exhibited limited and variable cellular immune responses, highlighting the need for improved vaccination and monitoring strategies in these high-risk populations.
Abstract from DOAJ. Public domain (CC0 1.0).
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