Publication date: Jun 05, 2025
Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion, which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada. Spike-specific CD4 and CD8 T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i. e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was not associated with increased T cell exhaustion in older frail adults, immunosuppressed individuals, or healthy adults.
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| Concepts | Keywords |
|---|---|
| Adults | Adults |
| Canada | Cov |
| Cd4 | Exhaustion |
| Immunosuppressive | Frail |
| Healthy | |
| Immune | |
| Individuals | |
| Older | |
| Populations | |
| Repeated | |
| Sars | |
| Specific | |
| Spike | |
| Vaccination | |
| Vulnerable |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | immune exhaustion |
| disease | MESH | T cell exhaustion |
| disease | IDO | quality |
| disease | IDO | cell |
| disease | IDO | production |
| disease | IDO | protein |
| disease | MESH | COVID 19 pandemic |
| pathway | REACTOME | Immune System |
| disease | MESH | infection |
| disease | MESH | Atherosclerosis |
| disease | MESH | rheumatoid arthritis |
| pathway | KEGG | Rheumatoid arthritis |
| drug | DRUGBANK | Coenzyme M |
| disease | IDO | blood |
| disease | MESH | chronic infections |
| drug | DRUGBANK | Trestolone |