Age. Children younger than six are at greatest risk of colds, especially if they spend time in child-care settings
Weakened immune system. Having a chronic illness or otherwise weakened immune system increases your risk.
Time of year. Both children and adults are more susceptible to colds in fall and winter, but you can get a cold any time.
Smoking. You’re more likely to catch a cold and to have more severe colds if you smoke.
Exposure. If you’re around many people, such as at school or on an airplane, you’re likely to be exposed to viruses that cause colds.