New research from Harvard Medical School has shown new first line defenses in the nose. The lining of the nose releases extracellular vesicles, or EVs. These particles act as decoys and viruses attach to them thinking they are cells. The vesicles then release micro strands of microRNA to disable the viruses. When the weather is cold the amount of EVs are decreased by 70%. This may explain why colds are more common in the winter months.