Influenza is a prolific and hazardous virus, affecting even those in the population who have been previously infected or vaccinated. The innate immune system serves as a key first line of defense against this pathogen, with the signaling components, called interferons, driving the production of a potent cellular antiviral response. Studies have indicated that viral populations replete in defective virus particles, virions with a deletion in a portion of their genome, are less efficient at blocking the antiviral response, as shown by increased interferon in the host. Our project seeks to explore this phenomenon of RNA deletions leading to increased interferon expression in host cells by testing the hypothesis that deletions in the three polymerase genes of influenza alone are sufficient to cause an increase in the interferon response. To begin answering this question, an interferon reporter system was used to analyze the viral genome of interferon positive cells, and deletions within various lengths of the PB1, PB2, and PA polymerase genes were found to be enriched. I then created pure populations of influenza with these empirically derived gene deletions in PB1 while my mentor, Dr. Alistair Russell, created pure PB2 deletion populations, which were grown on cell lines expressing functional PB1 and PB2 proteins respectively. When used to infect unmodified cell lines, it was found that pure populations of both PB1 and PB2 defective influenza were sufficient to induce the host interferon response. In the future, I will create PA expressing cell lines and influenza with deletions in PA to analyze the effect of PA deletions within the influenza genome on the host interferon response, and it is hoped that these results can be used to explore a mechanism for how influenza occasionally fails to escape the innate immune response.