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2009 swine flu outbreak

The H1NI swine flu virus was first detected in the UK on 27 April 2009, after first emerging in Mexico in February 2009.

On the same day, the World Health Organization raised the pandemic alert to a level 4, which signalled that the H1N1 virus was able to transmit from human to human.

The pandemic alert level reached level 6 (the maximum) on 11 June 2009, signalling the start of a pandemic – effectively a global outbreak of disease. Dr Margaret Chan, Director of the World Health Organization, stated that 'Influenza pandemics, whether moderate or severe, are remarkable events because of the almost universal susceptibility of the world's population to infection.'

The World Health Organization declared the pandemic officially over on 10 August 2010. The pandemic was considered to be mild, however, severe symptoms were seen in persons with underlying co-morbidities, the elderly and pregnant women.



Public Health England.
Influenza pandemics - history.
Public Health England; 2014.

Chan C.
World now at the start of 2009 influenza pandemic.
World Health Organisation; 2009.