Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-18T10:32:14.573Z Has data issue: false hasContentIssue false
  • English
  • Français

Spring 2009 H1N1 Influenza Outbreak in King County, Washington

Published online by Cambridge University Press:  08 April 2013

Tao Sheng Kwan-Gett ,
Atar Baer  and
Jeffrey S. Duchin
Get access Rights & Permissions [Opens in a new window]

Abstract

Background: In April 2009, King County, Washington, experienced a sustained outbreak of 2009 H1N1 influenza A. This report describes the epidemiology of that outbreak in King County, home to a diverse population of 1.9 million people.

Methods: The 2 primary sources of data are case investigations of reported laboratory-confirmed 2009 H1N1 influenza A and a population-based syndromic surveillance system that captures data from emergency departments (EDs). A syndromic category for influenza-like illness was defined based on chief complaint and diagnosis.

Results: ED visits for influenza-like illness peaked quickly in the first week of the outbreak and remained high for approximately 6 weeks, with school-age children accounting for the greater number of ED visits, followed by young adults. Children ages 0 to 4 years had the highest rate of hospitalization. Among reported cases, blacks, Asians, and Hispanics were more likely to be hospitalized. Predisposing factors associated with admission were immune compromise, chronic lung disease, chronic heart disease, pregnancy, diabetes, and asthma. Of people receiving antiviral treatment, 34% started their medication more than 2 calendar days after the onset of illness. Mean days between illness onset and antiviral treatment were greater for blacks, Hispanics, and foreign language speakers.

Conclusions: The spring 2009 influenza A H1N1 outbreak disproportionately affected children, young adults, and racial and ethnic minorities. Opportunities exist to improve the timeliness of antiviral treatment. Potential barriers to care for racial and ethnic minorities should be proactively addressed to ensure prompt evaluation and treatment. (Disaster Med Public Health Preparedness. 2009;3(Suppl 2):S109–S116)

Keywords

2009 H1N1public healthKing Countyepidemiology
Type
Research
Information
Disaster Medicine and Public Health Preparedness , Volume 3 , Issue S2 , December 2009 , pp. S109 - S116
Copyright
Copyright © Society for Disaster Medicine and Public Health, Inc. 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Swine influenza A (H1N1) infection in two children—southern California, March–April 2009. MMWR Morb Mortal Wkly Rep. 2009;58:400–402.Google Scholar
2.Hutwagner, L, Thompson, W, Seeman, GM, et alThe bioterrorism preparedness and response Early Aberration Reporting System (EARS). J Urban Health. 2003;80:i89–i96.Google Scholar
3.Official April 1, 2009, Population Estimates, Washington State Office of Financial Management. http://www.ofm.wa.gov/pop/april1/default.asp. Accessed October 7, 2009.Google Scholar
4.Summary Tables of April 1 Population Estimates by County by Race and Hispanic Origin, 2000 and 2008, Washington State Office of Financial Management. http://www.ofm.wa.gov/pop/race/summarytables08.asp. Accessed October 7, 2009.Google Scholar
5.Core Indicator: Obesity, Age 18 and Older, King County. http://www.kingcounty.gov/healthservices/health/data/chi/riskfactors/AdultObese.aspx. Accessed October 7, 2009.Google Scholar
6.Prevention and control of seasonal influenza with vaccines—recommendations of the Advisory Committee on Immunization Practices (ACIP), 2009. MMWR Morb Mortal Wkly Rep. 2009;58:1–52.Google Scholar
7.Harper, SA, Bradley, JS, Englund, JA, et alSeasonal influenza in adults and children—diagnosis, treatment, chemoprophylaxis, and institutional outbreak management: clinical practice guidelines of the Infectious Diseases Society of America. Clin Infect Dis. 2009;48:1003–1032.Google Scholar
8.Iwane, MK, Edwards, KM, Szilagyi, PG, et alPopulation-based surveillance for hospitalizations associated with respiratory syncytial virus, influenza virus, and parainfluenza viruses among young children. Pediatrics. 2004;113:1758–1764.Google Scholar
9.2009 pandemic influenza A (H1N1) virus infections—Chicago, Illinois, April–July 2009. MMWR Morb Mortal Wkly Rep. 2009;58:913–918.Google Scholar
10.Jain, S, Kamimoto, L, Bramley, AM, et alHospitalized patients with 2009 H1N1 influenza in the United States, April-June 2009. N Engl J Med. 2009. [Epub ahead of print].Google Scholar
11.Fiscella, K, Franks, P, Doescher, MP, et alDisparities in health care by race, ethnicity, and language among the insured: findings from a national sample. Med Care. 2002;40:52–59.Google Scholar
12.Asthma prevalence and control characteristics by race/ethnicity—United States, 2002. MMWR Morb Mortal Wkly Rep. 2004;53:145–148.Google Scholar
13.Prevalence of diabetes and impaired fasting glucose in adults—United States, 1999–2000. MMWR Morb Mortal Wkly Rep. 2003;52:833–837.Google Scholar
14.Differences in prevalence of obesity among black, white, and Hispanic adults—United States, 2006–2008. MMWR Morb Mortal Wkly Rep. 2009;58:740–744.Google Scholar
15.Linder, JA, Chan, JC, Bates, DWAppropriateness of antiviral prescribing for influenza in primary care: a retrospective analysis. Int J Clin Pharmacol Ther. 2006;31:245–252.Google Scholar