Azithromycin for Preventing the Development of Upper Respiratory Tract Illness Into Lower Respiratory Tract Symptoms in Children and Oral Corticosteroids for Treating Episodes of Significant Lower Respiratory Tract Symptoms in Children

This protocol is comprised of two separate, but linked, clinical trials for treating preschool-aged children with recurrent severe episodes of wheezing. The first study (APRIL) will try to prevent wheezing illness from developing using azithromycin. If a wheezing illness does occur, the second trial (OCELOT) will try to decrease the severity of symptoms using oral corticosteroids.