Live yellow fever vaccine (YF-17D)-specific memory CD8+ T cells exhibited a terminally differentiated CD45RA+CCR7− phenotype but remained polyfunctional with robust proliferative potential 5–10 years post vaccination, which may suggest that re-expressed CD45RA biomarks highly functional memory T cells after acute viral infections rather than senescent T cells (Akondy et al., 2009). This evidence concerns the gene CD8A and viral infectious disease.