Epidemiologic and virologic assessment of the 2009 influenza A (H1N1) pandemic on selected temperate countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa
Open Access
- 20 April 2011
- journal article
- research article
- Published by Wiley in Influenza and Other Respiratory Viruses
- Vol. 5 (6), e487-e498
- https://doi.org/10.1111/j.1750-2659.2011.00249.x
Abstract
Introduction and Setting Our analysis compares the most comprehensive epidemiologic and virologic surveillance data compiled to date for laboratory-confirmed H1N1pdm patients between 1 April 2009 - 31 January 2010 from five temperate countries in the Southern Hemisphere-Argentina, Australia, Chile, New Zealand, and South Africa. Objective We evaluate transmission dynamics, indicators of severity, and describe the co-circulation of H1N1pdm with seasonal influenza viruses. Results In the five countries, H1N1pdm became the predominant influenza strain within weeks of initial detection. South Africa was unique, first experiencing a seasonal H3N2 wave, followed by a distinct H1N1pdm wave. Compared with the 2007 and 2008 influenza seasons, the peak of influenza-like illness (ILI) activity in four of the five countries was 3-6 times higher with peak ILI consultation rates ranging from 35/1,000 consultations/week in Australia to 275/100,000 population/week in New Zealand. Transmission was similar in all countries with the reproductive rate ranging from 1.2-1.6. The median age of patients in all countries increased with increasing severity of disease, 4-14% of all hospitalized cases required critical care, and 26-68% of fatal patients were reported to have >= 1 chronic medical condition. Compared with seasonal influenza, there was a notable downward shift in age among severe cases with the highest population-based hospitalization rates among children <5 years old. National population-based mortality rates ranged from 0.8-1.5/100,000. Conclusions The difficulty experienced in tracking the progress of the pandemic globally, estimating its severity early on, and comparing information across countries argues for improved routine surveillance and standardization of investigative approaches and data reporting methods.Keywords
This publication has 34 references indexed in Scilit:
- Influenza A (H1N1) 2009 Antibodies in Residents of New South Wales, Australia, after the First Pandemic Wave in the 2009 Southern Hemisphere WinterPLOS ONE, 2010
- A lower than expected adult Victorian community attack rate for pandemic (H1N1) 2009Australian and New Zealand Journal of Public Health, 2010
- Influenza A pandemics: Clinical and organizational aspects: The experience in ChileCritical Care Medicine, 2010
- High mortality from respiratory failure secondary to swine-origin influenza A (H1N1) in South AfricaQJM: An International Journal of Medicine, 2010
- Community-Acquired Pneumonia Due to Pandemic A(H1N1)2009 Influenzavirus and Methicillin Resistant Staphylococcus aureus Co-InfectionPLOS ONE, 2010
- Pros and cons of estimating the reproduction number from early epidemic growth rate of influenza A (H1N1) 2009Theoretical Biology and Medical Modelling, 2010
- Critical Care Services and 2009 H1N1 Influenza in Australia and New ZealandThe New England Journal of Medicine, 2009
- Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress SyndromeJAMA, 2009
- Absenteeism in the nursing team in surgical-clinical units of a philanthropic hospitalActa Paulista de Enfermagem, 2008
- Influenza-Associated Hospitalizations in the United StatesJAMA, 2004