IFNA1 and viral infectious disease: This review consists of three sections: (1) the HBV life cycle and the classical IFN induction pathway in response to viral infection; (2) a systematic discussion of the crosstalk between IFN and HBV, with a focus on two-way inhibition: the inhibition of HBV infection and replication by ISGs as well as the inhibition of IFN signaling by HBV and HBV proteins; and (3) a brief discussion of the current IFN-based HBV treatment strategies.