The article highlights a study which describes a mechanism by which influenza A virus nonstructural protein 1 (NS1) inhibits the production of type I interferons (IFNs) and antiviral immunity. It indicates that NS1 inhibits the ubiquitylation of viral sensor retinoic acid-inducible gene I (RIG-I) by the ubiquitin ligase tripartite motif-containing 25 (TRIM25) with its downstream signalling partner. The results indicate the important role of NS1-mediated inhibition of the host type I IFN response.