Children hospitalized with 2009 novel influenza A(H1N1) in California

Janice K. Louie, Shilpa Gavali, Meileen Acosta, Michael C. Samuel, Kathleen Winter, Cynthia Jean, Carol A. Glaser, Bela T. Matyas, Robert Schechter

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Objective: To describe clinical and epidemiologic features of 2009 novel influenza A(H1N1) in children. Design: Analysis of data obtained from standardized report forms and medical records. Setting: Statewide public health surveillance in California. Participants: Three hundred forty-five children who were hospitalized with or died of 2009 novel influenza A(H1N1). Main Exposure: Laboratory-confirmed 2009 novel influenza A(H1N1). Main Outcome Measures: 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 on-set. 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.

Original languageEnglish
Pages (from-to)1023-1031
Number of pages9
JournalArchives of Pediatrics and Adolescent Medicine
Issue number11
StatePublished - Nov 2010

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


Dive into the research topics of 'Children hospitalized with 2009 novel influenza A(H1N1) in California'. Together they form a unique fingerprint.

Cite this