re regulatory T cells (Treg) (Bacher et al., 2016). Further analyses of S protein-specific T cells by ELISA demonstrated robust induction of IFN-γ, TNF-α, and IL-2 concomitant with lower levels of IL-5, IL-13, IL-9, IL-10, and IL-22. A third report focused on S-specific CD4 T cell responses in 18 patients with mild, severe,