"Swine flu" pandemic 2009-10
The virus was first identified in Mexico in April 2009. It became known as swine flu because it's similar to flu viruses that affect pigs.
It spread rapidly from country to country because it was a new type of flu virus that few young people were immune to.
Overall, the outbreak wasn't as serious as originally predicted, largely because many older people were already immune to it. Most cases in the UK were relatively mild – although serious cases still occurred.
The relatively small number of cases resulting in serious illness and death were mostly in younger adults and children – particularly those with underlying health problems – and pregnant women.
On August 10 2010, the World Health Organization (WHO) declared the pandemic officially over.
Introduction 