IFNB1 and infection: Finally, we observed an early induction of type I interferons (IFN-α and -β) at a very early time point (6h p.i.)of rhMPV-ΔG infection, which was not sustained at later time points, as the levels of type I interferons, in particular IFN-β, were significantly greater in rhMPV -WT-infected mice compared to rhMPV-ΔG (Figure 2B).