The characterization of CD8 T-cell responses in COVID-19.

This review gives an overview of the protective role of CD8 T cells in SARS-CoV-2 infection. The cross-reactive responses intermediated by CD8 T cells in unexposed cohorts are described. Additionally, the relevance of resident CD8 T cells in the upper and lower airway during infection and CD8 T-cell responses following vaccination are discussed, including recent worrisome breakthrough infections and variants of concerns (VOCs). Lastly, we explain the correlation between CD8 T cells and COVID-19 severity. This review aids in a deeper comprehension of the association between CD8 T cells and SARS-CoV-2 and broadens a vision for future exploration.