Children hospitalized with 2009 novel influenza A(H1N1) in California.
OBJECTIVE
To describe clinical and epidemiologic features of 2009 novel influenza A(H1N1) in children.


METHODS
Analysis of data obtained from standardized report forms and medical records.


METHODS
Statewide public health surveillance in California.


METHODS
Three hundred forty-five children who were hospitalized with or died of 2009 novel influenza A(H1N1).


METHODS
Laboratory-confirmed 2009 novel influenza A(H1N1).


METHODS
Hospitalization and death.


RESULTS
From April 23 to August 11, 2009, 345 cases in children younger than 18 years were reported. The median age was 6 years. The hospitalization rate per 100 000 per 110 days was 3.5 (0.97 per 100 000 person-months), with rates highest in infants younger than 6 months (13.9 per 100 000 or 3.86 per 100 000 person-months). Two-thirds (230; 67%) had comorbidities. More than half (163 of 278; 59%) had pneumonia, 94 (27%) required intensive care, and 9 (3%) died; in 3 fatal cases (33%), children had secondary bacterial infections. More than two-thirds (221 of 319; 69%) received antiviral treatment, 44% (88 of 202) within 48 hours of symptom onset. In multivariate analysis, congenital heart disease (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.9-13.5) and cerebral palsy/developmental delay (OR, 3.5; 95% CI, 1.7-7.4) were associated with increased likelihood of intensive care unit admission and/or death; likelihood was decreased in Hispanic (OR, 0.4; 95% CI, 0.2-0.8) and black (OR, 0.3; 95% CI, 0.1-1.0) children compared with white children.


CONCLUSIONS
More than one-quarter of children hospitalized with 2009 novel influenza A(H1N1) reported to the California Department of Public Health required intensive care and/or died. Regardless of rapid test results, when 2009 novel influenza A(H1N1) is circulating, clinicians should maintain a high suspicion in children with febrile respiratory illness and promptly treat those with underlying risk factors, especially infants.
California Department of Public Health, 850 Marina Bay Pkwy., Richmond, CA 94804, USA. janice.louie@cdph.ca.gov
Janice K
JK
Louie
Shilpa
S
Gavali
Meileen
M
Acosta
Michael C
MC
Samuel
Kathleen
K
Winter
Cynthia
C
Jean
Carol A
CA
Glaser
Bela T
BT
Matyas
Robert
R
Schechter
D000293:Adolescent; D000998:Antiviral Agents / Q000627:therapeutic use; D002140:California / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D003422:Critical Care / Q000706:statistics & numerical data; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000628:therapy / Q000821:virology; D008297:Male; D011159:Population Surveillance; D012307:Risk Factors
D000998:Antiviral Agents