Comparison of adult patients hospitalised with pandemic (H1N1) 2009 influenza and seasonal influenza during the "PROTECT" phase of the pandemic response

Craig B Dalton, Michelle A Cretikos, David N Durrheim, Ian M Seppelt, William D Rawlinson and Dominic E Dwyer
Med J Aust 2010; 192 (6): . || doi: 10.5694/j.1326-5377.2010.tb03547.x
Published online: 15 March 2010

To the Editor: Chang and colleagues suggest that the clinical course and outcomes of patients infected with pandemic (H1N1) 2009 influenza virus are comparable to those with seasonal influenza infection, and that increased hospital and intensive care unit (ICU) admissions with influenza reflected a higher incidence of disease in the community rather than enhanced virulence of the pandemic influenza virus.1 However, this conclusion was based on an analysis of data from a single hospital, which did not examine whether the community incidence of influenza was increased or whether infection with pandemic (H1N1) 2009 influenza increased the risk of admission to a hospital or ICU compared to infection with seasonal influenza.

  • Craig B Dalton1
  • Michelle A Cretikos2
  • David N Durrheim3
  • Ian M Seppelt1
  • William D Rawlinson4
  • Dominic E Dwyer5

  • 1 Hunter New England Population Health, Hunter New England Area Health Service, Newcastle, NSW.
  • 2 Centre for Epidemiology and Research, New South Wales Department of Health, Sydney, NSW.
  • 3 Department of Intensive Care Medicine, Nepean Hospital, Sydney, NSW.
  • 4 Virology Division, SEALS Microbiology, Sydney, NSW.
  • 5 Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Department of Virology, Westmead Hospital, Sydney, NSW.


We acknowledge the work of the eight NSW public hospital laboratories that contributed data, as well as the work of the NSW public health network and the NSW intensive care community.

Competing interests:

David Durrheim receives money for direct expenses and travel as a member of the World Health Organization Strategic Advisory Group of Experts (SAGE) on Immunization to the Director General.


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