Overview
Sneezing, scratchy throat, runny nose—everyone knows the first signs of a cold, probably the most common illness known. Common colds can be cause by over 200 viruses.
Although the common cold is usually mild, with symptoms lasting 1 to 2 weeks, it is a leading cause of doctor visits and missed days from school and work in the United States. According to the Centers for Diseases Control and Prevention (CDC), 22 million school days are lost annually in the United States due to the common cold.