At the time of the study no information was available in France about the i
ncidence of Reye's Syndrome (RS) and no warnings about RS and aspirin. The
objective was to evaluate the incidence of RS in France by a hospital-based
study. For a period of I year from November 1995 to November 1996, all Fre
nch paediatric departments were required to report any child under 15 years
with unexplained noninflammatory encephalopathy (i.e., CDC consciousness l
evel stage 1 or deeper with normal CSF) and a threefold (or greater) increa
se in serum aminotransferase and/or ammonia. All suspected cases were class
ified by a panel of experts as probable RS or excluded RS. In 10% of random
ly selected paediatric departments we checked that every suspected case had
been reported. Forty-six suspected casts were reported during the year of
the survey, of which 14 were classified as RS. Five of these 14 cases had a
metabolic disorder. Nine children were definitively diagnosed as having RS
(i.e., an estimated incidence of RS of 0.79/1,000,000 children, i.e., belo
w 15/year). Eight children had been exposed to aspirin, four to aspirin alo
ne and four to aspirin and acetaminophen. On the basis of these results the
incidence of RS in France in 1996-1997 was not substantially different fro
m that of countries where warning labels were already in use, but it was hi
gher than in the US after 1994. This was probably due to the reduction in a
spirin prescription in France because of warnings in Europe and the US and
also because many cases of RS are now identified as metabolic disease. On t
he basis of these results and because the relationship between aspirin and
RS has already been proved. public and professional warnings concerning RS
on aspirin-containing products in cases of varicella and viral febrile illn
ess have been adopted by the French Drugs Agency. (C) 2001 Elsevier Science
Inc. All rights reserved.