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
. 2010 Mar 9;182(4):349-55.
doi: 10.1503/cmaj.091823. Epub 2010 Feb 16.

Risk of severe outcomes among patients admitted to hospital with pandemic (H1N1) influenza

Alexia Campbell  1 , Rachel Rodin, Rhonda Kropp, Yang Mao, Zhiyong Hong, Julie Vachon, John Spika, Louise Pelletier
Affiliations

Risk of severe outcomes among patients admitted to hospital with pandemic (H1N1) influenza

Alexia Campbell et al. CMAJ. .

Abstract

Background: We describe the disease characteristics and outcomes, including risk factors for admission to intensive care unit (ICU) and death, of all patients in Canada admitted to hospital with pandemic (H1N1) influenza during the first five months of the pandemic.

Methods: We obtained data for all patients admitted to hospital with laboratory-confirmed pandemic (H1N1) influenza reported to the Public Health Agency of Canada from Apr. 26 to Sept. 26, 2009. We compared inpatients who had nonsevere disease with those who had severe disease, as indicated by admission to ICU or death.

Results: A total of 1479 patients were admitted to hospital with confirmed pandemic (H1N1) influenza during the study period. Of these, 1171 (79.2%) did not have a severe outcome, 236 (16.0%) were admitted to ICU and survived, and 72 (4.9%) died. The median age was 23 years for all of the patients, 18 years for those with a nonsevere outcome, 34 years for those admitted to ICU who survived and 51 years for those who died. The risk of a severe outcome was elevated among those who had an underlying medical condition and those 20 years of age and older. A delay of one day in the median time between the onset of symptoms and admission to hospital increased the risk of death by 5.5%. The risk of a severe outcome remained relatively constant over the five-month period.

Interpretation: The population-based incidence of admission to hospital with laboratory-confirmed pandemic (H1N1) influenza was low in the first five months of the pandemic in Canada. The risk of a severe outcome was associated with the presence of one or more underlying medical conditions, age of 20 years or more and a delay in hospital admission.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Severity of outcome by age among 1473 cases of pandemic (H1N1) influenza in patients admitted to hospital that were reported from Apr. 26 to Sept. 26, 2009. (Information on age missing for six patients.) ICU = intensive care unit.
Figure 2
Figure 2
Epidemic curve of laboratory-confirmed cases of pandemic (H1N1) influenza in patients admitted to hospital that were reported from Apr. 26 to Sept. 26, 2009, by date of symptom onset or collection of specimen.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. World Health Organization. Global influenza programme: global surveillance during an influenza pandemic, version 1. Geneva (Switzerland): The Organization; 2009. [(accessed 2009 Sept. 1)]. Available: www.who.int/csr/disease/swineflu/global_pandemic_influenza_surveilance_a....
    1. Public Health Agency of Canada. FluWatch: Definitions for the 2009–2010 season. Ottawa (ON): The Agency; 2009. [(accessed 2009 Nov. 25)]. Available: www.phac-aspc.gc.ca/fluwatch/09-10/def09-10-eng.php.
    1. National Advisory Committee on Immunization (NACI) Statement on influenza vaccination for the 2008–2009 season. [(accessed 2009 Nov. 1)];Can Commun Dis Rep. 2008 34(ACS-3):1–46. Available: www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08vol34/acs-3/index-eng.php. - PubMed
    1. Use of influenza A (H1N1) 2009 monovalent vaccine, recommendations of the Advisory Committee on Immunization Practices (ACIP), 2009. MMWR Recomm Rep. 2009;58(RR-10):1–8. - PubMed
    1. Age and sex highlight tables, 2006 census. Ottawa (ON): Statistics Canada; 2009. [(accessed 2009 Sept. 25)]. Available: www12.statcan.gc.ca/english/census06/data/highlights/agesex/index.cfm.

MeSH terms