While there were statistically significant differences in mortality of the 4-week-old CD4 depleted vs. control Ifnar1-/- mice (S2A Fig), the CD4 depleted mice did not lose significantly more weight (S2B Fig), and there were no dramatic differences in clinical disease signs (S2C Fig), or viral burden at days 4 or 7 post-infection (S2D–S2I Fig). This evidence concerns the gene IFNAR1 and infection.