Introduction

The runny nose, the scratchy throat, the stuffy, sneezy misery—the ordinary "common cold" can be extraordinarily bothersome and uncomfortable. Costly, too: in a typical year in the U.S., 1 billion colds cause 15 million days lost from work and 157 million days of restricted activity. Even more often, colds go with us—to daycare, to school, to work, to the movies and shopping, to restaurants and the family dinner table.

Scientists have learned a lot about colds—what causes them, when and whom they strike most often—but have not yet developed a quick cure or a preventive vaccine.

Knowledge can be powerful medicine, however, if you use it to lower your risk of catching a cold. Colds are everywhere and you are exposed to them routinely. But some simple steps can significantly reduce your chances of catching every cold you meet.