Count on us: T cells in SARS-CoV-2 infection and vaccination

Robust T cell responses have been associated with milder outcomes in many infections. T cells also establish long-term memory pools and, as they are predominantly directed toward epitopes encompassing conserved peptides, can respond to SARS-CoV-2 variants, including Omicron. Here, we discuss epitope-specific CD8(+) and CD4(+) T cell responses toward SARS-CoV-2 infection and vaccination, their subsequent persistence into long-term memory, and ongoing work to determine their role in limiting disease severity.