IFNAR1 and obesity due to melanocortin 4 receptor deficiency: To determine if blunted IFN levels alone in the absence of obesity could impact viral clearance, IFNAR−/− or WT male and female mice were treated with 10 mg/kg OSV or vehicle control (PBS) and inoculated intranasally with CA/09 H1N1 virus or PBS as in Fig. 1A.