Interferon (IFN)-alpha is made by cells to fight viruses and used as a therapy, but suffers from undesirable formulation to prevent degradation and clearance. We discovered that MMP12 degrades and clears IFN-alpha; in viral infections yet is also essential for IFN-alpha expression. We invented a MMP12-specific inhibitor. The drug eliminated viral replication in mice by boosting levels of all IFN-alpha; isoforms. As most viruses succumb to IFN-alpha; this broad-acting treatment is significant in the fight against infections.