While estimates of 2009 H1N1-associated deaths have been derived for some countries such as the US, these are the first estimates of the worldwide number of deaths caused by the pandemic, said the report published in The Lancet Infectious Diseases today.
The new research indicates that an estimated 151,700 to 575,400 people died from swine flu between in the first year when the virus spread worldwide. The casualty figure is almost 15 times more than the 18,500 H1N1-related deaths reported between April 2009 to August 2010, the researchers said.
The results suggested that 80 per cent of the deaths occurred in people younger than 65 years, contrary to seasonal influenza where most deaths occur among the elderly.
As the pandemic -- which spread to some 214 countries and territories after it was uncovered in Mexico and the US in April 2009 -- affected younger populations more than older populations, the global burden in terms of years of life lost was higher during this pandemic than it would be for a typical influenza season.
Additionally, the study suggested that 51 per cent of the deaths may have occurred in southeast Asia and Africa, which homes about 38 per cent of the world's population, with the highest mortality rates occurring in Africa.
"The study underscores the significant human toll of an influenza pandemic," said lead author Dr Fatimah Dawood of the US' Centers for Disease Control and Prevention.
"We hope that this work can be used not only to improve influenza disease burden modelling globally, but to improve the public health response during future pandemics in parts of the world that suffer more deaths, and to increase the public awareness of the importance of influenza prevention." (More)