A total of 1207 cases of Reye syndrome were reported to the Centers for Disease Control and Prevention (CDC) between 1980 and 1997.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
The peak incidence occurred in 1980, with 555 cases reported. The incidence has steadily declined since 1980, possibly due to overdiagnosis in previous years, improved metabolic testing, lower prevalence of influenza, and a decline in pediatric aspirin consumption. Since 1994, there have been 2 or fewer cases reported per year in the US. The 2009 incidence is thought to be between <0.3 and 1.0/100,000 in people <18 years old.[6]Schror K. Aspirin and Reye syndrome: a review of the evidence. Paediatr Drugs. 2007;9(3):195-204.
http://www.ncbi.nlm.nih.gov/pubmed/17523700?tool=bestpractice.com
[7]Fitzgerald DA. Aspirin and Reye syndrome. Paediatr Drugs. 2007;9(3):205-6.
http://www.ncbi.nlm.nih.gov/pubmed/17523701?tool=bestpractice.com
[8]Casteels-Van Daele M, Van Geet C, Wouters C, et al. Reye syndrome revisited: a descriptive term covering a group of heterogeneous disorders. Eur J Pediatr. 2000 Sep;159(9):641-8.
http://www.ncbi.nlm.nih.gov/pubmed/11014461?tool=bestpractice.com
The exact incidence is difficult to establish because reporting cases of Reye syndrome to the CDC is no longer mandated.[9]Chapman J, Arnold JK. Reye syndrome. StatPearls Publishing; 2019.
https://www.ncbi.nlm.nih.gov/books/NBK526101
http://www.ncbi.nlm.nih.gov/pubmed/30252357?tool=bestpractice.com
Of the 1207 cases of Reye syndrome reported to the CDC between 1980 to 1997, 93% occurred in white patients; 5% of patients were black, 2% were Asian, and 0.3% were Native American or Native Alaskan.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
There was no sex predilection. Peak age of incidence was between 5 and 14 years, with a median of 6 years and a mean of 7 years.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
Antecedent viral illness during the three week period prior to onset of Reye syndrome, most commonly respiratory, was reported in 93% of patients (n=1080) for whom data was available (n=1160).[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
An increase in the number of cases in the US was found during the months of December through April, which correlated with the peak occurrences of most viral respiratory infections.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
Since the 1990s, this seasonal association has diminished. Globally, a seasonal predominance has not been found.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
Reye syndrome rarely occurs in children <1 year old or in those ages >18 years old.[5]Belay ED, Bresee JS, Holman RC, et al. Reye's syndrome in the United States from 1981 through 1997. N Engl J Med. 1999 May 6;340(18):1377-82.
http://www.nejm.org/doi/full/10.1056/NEJM199905063401801#t=article
http://www.ncbi.nlm.nih.gov/pubmed/10228187?tool=bestpractice.com
[10]Khater F, Moorman JP. Complications of influenza. South Med J. 2003 Aug;96(8):740-3.
http://www.ncbi.nlm.nih.gov/pubmed/14515911?tool=bestpractice.com
In the UK and Ireland, 264 cases of Reye syndrome were reported between 1981 and 1985; only 5 cases were reported between 1996 and 1997.[11]Hall SM, Plaster PA, Glasgow JF, et al. Preadmission antipyretics in Reye's syndrome. Arch Dis Child. 1988 Jul;63(7):857-66.
https://www.doi.org/10.1136/adc.63.7.857
http://www.ncbi.nlm.nih.gov/pubmed/3415311?tool=bestpractice.com
[6]Schror K. Aspirin and Reye syndrome: a review of the evidence. Paediatr Drugs. 2007;9(3):195-204.
http://www.ncbi.nlm.nih.gov/pubmed/17523700?tool=bestpractice.com
[12]Guy M, Nicoll A, Lynn R. British Paediatric Surveillance Unit. 12th annual report. London: Royal College of Paediatrics and Child Health; 1998. Surveillance activities in 1997;8-10. Reye syndrome is a rare diagnosis in continental Europe and Asia.[6]Schror K. Aspirin and Reye syndrome: a review of the evidence. Paediatr Drugs. 2007;9(3):195-204.
http://www.ncbi.nlm.nih.gov/pubmed/17523700?tool=bestpractice.com