Our data supports the hypothesis that ILL-D1 T-cell responses display stronger correlations with virologic outcomes than nAb levels due to differential kinetics of the cellular and humoral response following breakthrough infection as demonstrated by the high level of ILL-D1 CD4+ and CD8+ T-cell response observed in vaccinees compared with placebo (CD4+ 93% versus 50%; CD8+ 67% versus 25%). Here, CD8A is linked to infection.