How Come Only Some People Catch Colds?

Whether you catch a cold this winter or make it through the season scot-free may depend in part on how many "stressors" your nose and airway passages encounter, a new study suggests.

The research looked at two defense mechanisms that cells in a person's airway use to protect themselves from threats: one that protects against viruses like the common cold virus and another that protects against "oxidative stress." This form of cell damage is triggered by viruses and other irritants, such as cigarette smoke or pollen.