In light of the 2009 influenza pandemic and potential future pandemics, Maria Van Kerkhove and colleagues anticipate six public health challenges and the data needed to support sound public health decision making.
Please cite this paper as: Van Kerkhove et al. (2011) 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. Influenza and Other Respiratory Viruses 5(6), e487–e498. 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.
In April 2009, the World Health Organization (WHO) reported the emergence of a new influenza (H1N1) virus which led to the first pandemic declaration of the 21st century. Most countries in Latin America and the Caribbean (LAC) had a national preparedness plan in place at this time; however, the vaccination component of such plans was largely undeveloped. Nevertheless, countries were able to capitalize on the infrastructure of their immunization programs and widespread experience utilizing the seasonal influenza vaccine to prepare rapidly, developing H1N1 vaccination plans targeting individuals with chronic disease, pregnant women and health care workers, among others. In LAC vaccine was acquired through three mechanisms: the Pan American Health Organization's Revolving Fund, direct manufacturer purchase, and WHO donations. Vaccine access was not equitable both in quantity of vaccine available and timeless of vaccine availability. As of December 2010, an estimated 145 million doses had been administered in LAC. Despite high regional coverage, there were large variations in coverage at the national level; pregnant women had the lowest coverage, despite their high risk for morbidity and mortality. The number of severe adverse events reported in LAC was similar to those expected with the seasonal influenza vaccine. Risk communication was one of the key challenges countries faced, mainly due to concerns and misinformation spread regarding vaccine safety. Countries and the international community need to learn from the experiences gained during H1N1 vaccination in order to be better prepared for the next pandemic.
Please cite this paper as: Azziz‐Baumgartner et al. (2012) Incidence of influenza‐associated mortality and hospitalizations in Argentina during 2002–2009. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12022. Background We estimated rates of influenza‐associated deaths and hospitalizations in Argentina, a country that recommends annual influenza vaccination for persons at high risk of complications from influenza illness. Methods We identified hospitalized persons and deaths in persons diagnosed with pneumonia and influenza (P&I, ICD‐10 codes J10‐J18) and respiratory and circulatory illness (R&C, codes I00‐I99 and J00‐J99). We defined the influenza season as the months when the proportion of samples that tested positive for influenza exceeded the annual median. We used hospitalizations and deaths during the influenza off‐season to estimate, using linear regression, the number of excess deaths that occurred during the influenza season. To explore whether excess mortality varied by sex and whether people were age <65 or ≥65 years, we used Poisson regression of the influenza‐associated rates. Results During 2002–2009, 2411 P&I and 8527 R&C mean excess deaths occurred annually from May to October. If all of these excess deaths were associated with influenza, the influenza‐associated mortality rate was 6/100 000 person‐years (95% CI 4–8/100 000 person‐years for P&I and 21/100 000 person‐years (95% CI 12–31/100 000 person‐years) for R&C. During 2005–2008, we identified an average of 7868 P&I excess hospitalizations and 22 994 R&C hospitalizations per year, resulting in an influenza‐associated hospitalization rate of 2/10 000 person‐years (95% CI 1–3/10 000 person‐years) for P&I and 6/10 000 person‐years (95% CI 3–8/10 000 person‐years) for R&C. Conclusion Our findings suggest that annual rates of influenza‐associated hospitalizations and death in Argentina were substantial and similar to neighboring Brazil.
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