Reye's syndrome was first identified as a distinct disease in 1963, and the number of recognized cases began to increase in the 1970s. In 1980 the number of cases in the United States peaked at 555. After that, the figures began a sharp decline. In fact, from 1984 to 1994 there were no more than 36 cases of Reye's syndrome a year. Since then only a few cases have been reported each year.
Many people assume the decline is because of the warnings against children taking aspirin.
But that may be only part of the reason. There are now better tests to diagnose metabolic conditions formerly thought to be Reye's syndrome. Indeed, many children thought to have had Reye's syndrome in the 1970s may have had other metabolic conditions that couldn't be diagnosed. Today children who do develop Reye's syndrome or conditions once thought to be Reye's syndrome are being diagnosed earlier and receiving better treatment, helping improve recovery and reduce complications. The signs and symptoms of Reye's syndrome typically begin about 1 week after a viral infection such as influenza or chickenpox .