Pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1) in Argentina.
BACKGROUND
While the Northern Hemisphere experiences the effects of the 2009 pandemic influenza A (H1N1) virus, data from the recent influenza season in the Southern Hemisphere can provide important information on the burden of disease in children.


METHODS
We conducted a retrospective case series involving children with acute infection of the lower respiratory tract or fever in whom 2009 H1N1 influenza was diagnosed on reverse-transcriptase polymerase-chain-reaction assay and who were admitted to one of six pediatric hospitals serving a catchment area of 1.2 million children. We compared rates of admission and death with those among age-matched children who had been infected with seasonal influenza strains in previous years.


RESULTS
Between May and July 2009, a total of 251 children were hospitalized with 2009 H1N1 influenza. Rates of hospitalization were double those for seasonal influenza in 2008. Of the children who were hospitalized, 47 (19%) were admitted to an intensive care unit, 42 (17%) required mechanical ventilation, and 13 (5%) died. The overall rate of death was 1.1 per 100,000 children, as compared with 0.1 per 100,000 children for seasonal influenza in 2007. (No pediatric deaths associated with seasonal influenza were reported in 2008.) Most deaths were caused by refractory hypoxemia in infants under 1 year of age (death rate, 7.6 per 100,000).


CONCLUSIONS
Pandemic 2009 H1N1 influenza was associated with pediatric death rates that were 10 times the rates for seasonal influenza in previous years.
Libster
Romina
R
Fundación INFANT, Buenos Aires.
Bugna
Jimena
J
Coviello
Silvina
S
Hijano
Diego R
DR
Dunaiewsky
Mariana
M
Reynoso
Natalia
N
Cavalieri
Maria L
ML
Guglielmo
Maria C
MC
Areso
M Soledad
MS
Gilligan
Tomas
T
Santucho
Fernanda
F
Cabral
Graciela
G
Gregorio
Gabriela L
GL
Moreno
Rina
R
Lutz
Maria I
MI
Panigasi
Alicia L
AL
Saligari
Liliana
L
Caballero
Mauricio T
MT
Egües Almeida
Rodrigo M
RM
Gutierrez Meyer
Maria E
ME
Neder
Maria D
MD
Davenport
Maria C
MC
Del Valle
Maria P
MP
Santidrian
Valeria S
VS
Mosca
Guillermina
G
Garcia Domínguez
Mercedes
M
Alvarez
Liliana
L
Landa
Patricia
P
Pota
Ana
A
Boloñati
Norma
N
Dalamon
Ricardo
R
Sanchez Mercol
Victoria I
VI
Espinoza
Marco
M
Peuchot
Juan Carlos
JC
Karolinski
Ariel
A
Bruno
Miriam
M
Borsa
Ana
A
Ferrero
Fernando
F
Bonina
Angel
A
Ramonet
Margarita
M
Albano
Lidia C
LC
Luedicke
Nora
N
Alterman
Elias
E
Savy
Vilma
V
Baumeister
Elsa
E
Chappell
James D
JD
Edwards
Kathryn M
KM
Melendi
Guillermina A
GA
Polack
Fernando P
FP
D000293:Adolescent; D017677:Age Distribution; D001118:Argentina / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D004196:Disease Outbreaks; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000401:mortality; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000145:classification / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000209:etiology; D012720:Severity of Illness Index; D013210:Staphylococcus / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000302:isolation & purification