Influenza-associated pneumonia in children hospitalized with laboratory-confirmed influenza, 2003-2008.
BACKGROUND
Pneumonia is one of the most common complications in children hospitalized with influenza. We describe hospitalized children with influenza-associated pneumonia and associated risk indicators.


METHODS
Through Emerging Infections Program Network population based surveillance, children aged <18 years hospitalized with laboratory confirmed influenza with a chest radiograph during hospitalization were identified during the 2003-2008 influenza seasons. A case with radiologically confirmed influenza-associated pneumonia was defined as a child from the surveillance area hospitalized with: (1) laboratory-confirmed influenza and (2) evidence of new pneumonia on chest radiograph during hospitalization. Hospitalized children with pneumonia were compared with those without pneumonia by univariate and multivariate analysis.


RESULTS
Overall, 2992 hospitalized children with influenza with a chest radiograph were identified; 1072 (36%) had influenza-associated pneumonia.When compared with children hospitalized with influenza without pneumonia, hospitalized children with influenza-associated pneumonia were more likely to require intensive care unit admission (21% vs. 11%, P < 0.01), develop respiratory failure (11% versus 3%, P < 0.01), and die(0.9% vs. 0.3% P 0.01). In multivariate analysis, age 6 to 23 months(adjusted OR: 2.1, CI: 1.6 -2.8), age 2 to 4 years (adjusted OR: 1.7, CI:1.3-2.2), and asthma (adjusted OR: 1.4, CI: 1.1-1.8) were significantly associated with influenza-associated pneumonia.


CONCLUSIONS
Hospitalized children with influenza-associated pneumonia were more likely to have a severe clinical course than other hospitalized children with influenza, and children aged 6 months to 4 years and those with asthma were more likely to have influenza-associated pneumonia.Identifying children at greater risk for influenza-associated pneumonia will inform prevention and treatment strategies targeting children at risk for influenza complications.
Dawood
Fatimah S
FS
Epidemic Intelligence Service, Centers forDisease Control and Prevention , Atlanta, GA, USA. fdawood@cdc.gov
Fiore
Anthony
A
Kamimoto
Laurie
L
Nowell
Mackenzie
M
Reingold
Arthur
A
Gershman
Kem
K
Meek
James
J
Hadler
James
J
Arnold
Kathryn E
KE
Ryan
Patricia
P
Lynfield
Ruth
R
Morin
Craig
C
Baumbach
Joan
J
Zansky
Shelley
S
Bennett
Nancy M
NM
Thomas
Ann
A
Schaffner
William
W
Kirschke
David
D
Finelli
Lyn
L
D000293:Adolescent; D000367:Age Factors; D001249:Asthma / Q000150:complications; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009980:Influenza A virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000150:complications*; D008297:Male; D018410:Pneumonia, Bacterial / Q000150:complications / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology; D013902:Radiography, Thoracic; D012131:Respiratory Insufficiency / Q000453:epidemiology; D012307:Risk Factors