IFNA1 and hepatitis B virus infection: PEG-IFN α-2a and PEG-IFN α-2b, two distinct pegylated interferon formulations, are employed in the treatment of hepatitis B. The mechanistic rationale for combining NAs and PEG-IFN involves the observation that these two classes of drugs have differential effects on innate and adaptive immunity and that viral suppression mediated by NAs directly enhances the subsequent immunologic response to PEG-IFN [13, 14].