H1N1 flu pandemic killed up to 203,000 people worldwide, study finds

[News_Editor]

WASHINGTON, D.C. (BNO NEWS) -- The H1N1 influenza virus, which quickly spread around the world in 2009, claimed the lives of up to 203,000 people, more than 10 times higher than the official death toll, according to an international study. A majority of the victims were under the age of 65.

H1N1, which is often referred to as swine flu because it originated in pigs, first emerged in the Mexican state of Veracruz in April 2009 and quickly began to spread, spreading to all continents in less than 9 weeks and throughout the world in 10 months. It led the World Health Organization (WHO) to declare a global flu pandemic in June 2009.

A total of 18,631 laboratory-confirmed deaths across 125 countries were reported to the WHO during the pandemic, which was declared over in August 2010, although the strain continues as a seasonal virus. Health officials have long recognized that the actual death toll was significantly higher.

A research team consisting of more than 60 collaborators in 26 countries has now estimated the death toll from the worst part of the pandemic - the last nine months of 2009 - to be between 123,000 and 203,000. This is lower than the on average 250,000 to 500,000 deaths per year caused by seasonal influenza, but the majority of people who died from H1N1 were under the age of 65.

"This study confirms that the H1N1 virus killed many more people globally than originally believed," said lead author Lone Simonsen, a research professor in the Department of Global Health at the George Washington University School of Public Health and Health Services. "We also found that the mortality burden of this pandemic fell most heavily on younger people and those living in certain parts of the Americas."

The 'low' number of confirmed deaths initially led to criticism which labeled the public health response as 'excessive,' but many did not take into account that most people infected with H1N1 did not receive a lab test, which is required to be included in the WHO's official count. However, the death toll remains low when compared with other events such as the 1918 Spanish flu pandemic, which killed up to 100 million people worldwide.

To determine the number of victims from the 2009 pandemic, researchers used weekly virology data from the WHO and actual mortality data from 21 countries. They used the information to estimate the number of respiratory deaths, which often occur when H1N1 gets into the lungs and causes pneumonia, and applied a novel statistical procedure to project those results to the rest of the world.

In addition to deaths caused by respiratory diseases, the H1N1 virus can also kill by exacerbating existing health problems, but these deaths were not included in the figure that put the death toll as up to 203,000. When including H1N1 deaths due to cardiovascular disease and other causes, the overall death toll from the pandemic could be as high as 400,000.

The WHO-funded study also showed a striking regional pattern as H1N1 swept through certain countries, leaving a substantial number of deaths in its wake. For example, the researchers found an almost 20-fold higher mortality rate in some countries in the Americas, with Mexico, Argentina and Brazil showing the highest respiratory death rates in the world. In contrast, the toll was far lower in New Zealand, Australia and most parts of Europe.

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