25 January 2013
Updated at 08:44 ET
Swine flu infected 'fifth of people'
James Gallagher
Health and Science reporter, BBC News
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At least one in five people, including half of schoolchildren, were infected with swine flu during the first year of the pandemic in 2009, according to data from 19 countries.
link-
http://www.bbc.co.uk/news/health-21194090