Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2010 Sep;16(9):1388-95.
doi: 10.3201/eid1609.100076.

Comparison of pandemic (H1N1) 2009 and seasonal influenza, Western Australia, 2009

Dale Carcione  1 , Carolien Giele, Gary K Dowse, Donna B Mak, Leigh Goggin, Kelly Kwan, Simon Williams, David Smith, Paul Effler
Affiliations
Comparative Study

Comparison of pandemic (H1N1) 2009 and seasonal influenza, Western Australia, 2009

Dale Carcione et al. Emerg Infect Dis. 2010 Sep.

Abstract

We compared confirmed pandemic (H1N1) 2009 influenza and seasonal influenza diagnosed in Western Australia during the 2009 influenza season. From 3,178 eligible reports, 984 pandemic and 356 seasonal influenza patients were selected; 871 (88.5%) and 288 (80.9%) were interviewed, respectively. Patients in both groups reported a median of 6 of 11 symptoms; the difference between groups in the proportion reporting any given symptom was < or =10%. Fewer than half the patients in both groups had > or =1 underlying condition, and only diabetes was associated with pandemic (H1N1) 2009 influenza (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.1-3.5). A total of 129 (14.8%) persons with pandemic (H1N1) 2009 and 36 (12.5%) persons with seasonal influenza were hospitalized (p = 0.22). After controlling for age, we found that patient hospitalization was associated with pandemic (H1N1) 2009 influenza (OR 1.5; 95% CI 1.1-2.1). Contemporaneous pandemic and seasonal influenza infections were substantially similar in terms of patients' symptoms, risk factors, and proportion hospitalized.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Number of notifications for pandemic and seasonal influenza, by date of onset and type, Western Australia, May 22–September 11, 2009. Influenza subtypes reported during the study period (n = 3,178): pandemic (H1N1) 2009, 2,794 (87.9%); influenza A (H3N2), 253 (8.0%); seasonal influenza A (H1N1), 89 (2.8%); influenza B, 36 (1.1%); and seasonal influenza A (not subtyped), 6 (0.2%).
Figure 2
Figure 2
Recruitment of pandemic and seasonal influenza study participants, Western Australia, 2009.
Figure 3
Figure 3
Age distribution for study participants, by influenza type, Western Australia, 2009.
Figure 4
Figure 4
Number of symptoms reported by study participants with influenza, by influenza type, Western Australia, 2009.
Figure 5
Figure 5
Number of underlying medical conditions reported by study participants, by influenza type, Western Australia, 2009.
Figure 6
Figure 6
Duration of hospital stay for study participants, by influenza type, Western Australia, 2009.
See this image and copyright information in PMC

Comment in

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Centers for Disease Control and Prevention. Swine influenza A (H1N1) infection in two children—southern California, March–April 2009. MMWR Morb Mortal Wkly Rep. 2009;58:400–2. - PubMed
    1. Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team; Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, et al. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med. 2009;360:2605–15. 10.1056/NEJMoa0903810 - DOI - PubMed
    1. Australian Government Department of Health and Ageing. First case of human swine influenza detected in Australia. H1N1 influenza 09 latest news. 2009. May 9 [cited 2010 Jan 17]. http://www.healthemergency.gov.au/internet/healthemergency/publishing.ns...
    1. Ong AK, Chen MI, Lin L, Tan AS, Nwe NW, Barkham T, et al. Improving the clinical diagnosis of influenza–a comparative analysis of new influenza A (H1N1) cases. PLoS ONE. 2009;4:e8453. 10.1371/journal.pone.0008453 - DOI - PMC - PubMed
    1. McBryde ES, Bergeri I, van Gemert C, Rotty J, Headley EJ, Simpson K, et al. Early transmission characteristics of influenza A(H1N1)v in Australia: Victorian state, 16 May–3 June 2009. Euro Surveill. 2009;14(42):pii=19363 [cited 2010 Jan 17]. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19363 - PubMed

Publication types

LinkOut - more resources