IFNA1 and infection: We also assumed that PEG IFN-α treatment is potent enough that intracellular HBV replication and de novo infections are negligible after treatment initiation [25,26,32–34], i.e., the antiviral effect of PEG IFN-α on intracellular HBV replications is assumed to be 0<ε≤1 andi(t,a)={0t>ai0(a)t<a.