Four- to six-month-old male ferrets were immunized i.m. with a single dose of HA from A/California/07/09 (15 μg) adjuvanted with either monoaxial Ace-DEX cGAMP MPs (15 μg cGAMP in 1.5 mg MPs) or AddaVax (9.75 mg squalene). Animals in the cGAMP MPs (2X) group received a boost with the same formulation 4 weeks later. (A) Serum was collected monthly and virus neutralizing titers against A/California/07/09 were assessed. (n=4 ± SD, *p < 0.05). One year after immunization, ferrets were challenged intranasally with 1.25 × 107 FFU of influenza strain A/California/07/09. Nasal lavage was collected (B) day 2 and (C) day 4 post challenge and viral load was assessed by foci forming assay. (D) Animal weights and (E) the periodic combined clinical index, a composite measure of animal activity and respiratory index (sneezing and nasal discharge), were assessed daily following infection. (n=4 ± SD, *p < 0.05, ****p < 0.0001).