Reye's Syndrome - Epidemiology

Epidemiology

Reye’s syndrome occurs almost exclusively in children. While a few adult cases have been reported over the years, these cases do not typically show permanent neural or liver damage. Unlike in the UK, the surveillance for Reye’s syndrome in the US is focused on patients under 18 years of age.

In 1980, after CDC began cautioning physicians and parents about the association between Reye’s syndrome and the use of salicylates in children with chickenpox or viruslike illnesses, the incidence of Reye's syndrome in the United States began to decline. In the United States between 1980 and 1997, the number of reported cases of Reye’s syndrome decreased from 555 cases in 1980 to about 2 cases per year since 1994. During this time period 93% of reported cases for which racial data were available occurred in whites and the median age was six years. In 93% of cases a viral illness had occurred in the preceding three week period. For the period 1991-1994, the annual rate of hospitalizations due to Reye’s syndrome in the US was estimated to be between 0.2 and 1.1 per million population less than 18 years of age.

During the 1980s, a case-control study carried out in the United Kingdom also demonstrated an association between Reye’s syndrome and aspirin exposure. In June 1986, the United Kingdom Committee on Safety of Medicines issued warnings against the use of aspirin in children under 12 years of age and warning labels on aspirin-containing medications were introduced. UK surveillance for Reye’s syndrome documented a decline in the incidence of the illness after 1986. The reported incidence rate of Reye’s syndrome decreased from a high of 0.63 per 100,000 population less than 12 years of age in 1983/84 to 0.11 in 1990/91.

From November 1995 to November 1996 in France, a national survey of pediatric departments for children under 15 years of age with unexplained encephalopathy and a threefold (or greater) increase in serum aminotransferase and/or ammonia led to the identification of nine definite cases of Reye’s syndrome (0.79 cases per million children). Eight of the nine children with Reye’s syndrome were found to have been exposed to aspirin. In part because of this survey result, the French Medicines Agency reinforced the international attention to the relationship between aspirin and Reye’s syndrome by issuing its own public and professional warnings about this relationship.