Received 20 August
2002; accepted 22 October 2002; electronically published 20 January 2003.
To obtaindata on the clinicalmanifestations
of infection, theage distribution, and theunderlying
conditions of childrenwith influenza severe enoughto
lead to hospitalreferral, we performed a
retrospective study of childrentreated at Turku UniversityHospital (Turku, Finland) in19801999.
Influenza A orB antigen was detectedin the
nasopharyngeal aspiratesof 683 of the15,420 children
studied. Themedian age of childrenwith influenza A
was2.0 years (n =544), and that of
children with influenza Bwas 4.2 years (n=
139) (P <.001). One-fourth of thechildren had
an underlyingmedical condition. High fever,cough,
and rhinorrhea werethe most frequently recorded
symptoms. Acute otitis mediadeveloped in 24% ofthe
children, and pneumoniadeveloped in 9% ofthe
children. The studyshows that the majorityof patient
hospitalizations forpediatric influenza involve previouslyhealthy infants and youngchildren. Laboratory confirmation
ofinfluenza is particularly importantfor children
because theclinical presentation of theinfection is
less characteristicthan that seen inadults.
Financial support: Academy ofFinland
(Helsinki, Finland). a Present affiliation:Department of Infectious Diseases,St. Jude Children's ResearchHospital, Memphis, Tennessee.
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1999.
Influenza A or B antigen was detected in the
nasopharyngeal aspirates of 683 of the 15,420 children
studied. The median age of children with influenza A
was 2.0 years (n = 544), and that of
children with influenza B was 4.2 years (n =
139) (P < .001). One-fourth of the children had
an underlying medical condition. High fever, cough,
and rhinorrhea were the most frequently recorded
symptoms. Acute otitis media developed in 24% of the
children, and pneumonia developed in 9% of the
children. The study shows that the majority of patient
hospitalizations for pediatric influenza involve previously
healthy infants and young children. Laboratory confirmation
of influenza is particularly important for children
because the clinical presentation of the infection is
less characteristic than that seen in adults.