IL2 and viral infectious disease: Considering the high IgG2a/IgG1 ratio (Figs. 4C and 5C) and the clear induction of HA specific T cells that produce IL-2 and IFN-γ (Fig. 4H, I and Supplementary Fig. S4E, F), we conclude that our HA sa-mRNA vaccines induced a Th1-skewed response, favoring the elimination of viral infections.