Reye syndrome and salicylates.

This year in the United States there has been considerable controversy about circumstantial evidence linking salicylates to the pathogenesis of Reye syndrome and, in particular, whether that evidence is sufficiently strong to justify action. After careful review both the Federal government and the American Academy of Pediatrics have warned physicians and parents of the possible risk of Reye syndrome in children who receive aspirin for varicella or influenza-like illnesses. For the past several years between 200 and 500 cases of Reye syndrome have been reported under a voluntary surveillance system. Undoubtedly many cases are not reported; the Centers for Disease Control estimates that the true annual figure is probably 600 to 1200 cases. Extrapolation of data from Ohio and Michigan where surveillance has been more intense suggests the number may be even higher—1600 to 3200 cases annually. Case-fatality rates range from 22 to 42%.' The majority of cases of Reye syndrome have been associated with influenza, usually influenza B; in approximately 20% of cases the inciting illness is chicken pox; the remainder are associated with a variety of other viral illnesses. Hypotheses to explain why only certain children with these viral illnesses develop Reye syndrome have ranged from genetic predisposition to various environmental factors, such as insecticides, and to medication administered for the antecedent viral illness. But these were only hypotheses until the second half of 1980, when summaries of five case control studies of Reye syndrome conducted in Arizona, Ohio and Michigan were published. Full reports of these studies are now published .~