In the United States, an estimated 1 billion upper respiratory tract infections and colds occur annually.1 Acute respiratory tract infections account for 10% of the 1.3 billion annual ambulatory and emergency department visits in the United States.2 Patients seeking medical care for acute respiratory tract infections have decrements in health-related quality of life that are similar in magnitude to those of patients with chronic lung disease, osteoarthritis, and depression.3 For these reasons, an effective preventive measure or cure for the common cold would reduce medical costs and improve quality of life.