Influenza A Virus Subtype H1N1

On April 25, 2009, the U.S. Centers for Disease Control and Prevention declared the outbreak of Influenza A H1N1 virus, commonly known as swine flu, to be a public health emergency. The spread of the virus required governments to provide guidance to the public about this health threat, including information on limiting the spread of the disease. In compliance with this requirement, in September 2009, the Food and Drug Administration announced the approval of four H1N1 influenza vaccinations. Information about swine flu was disseminated through traditional television, radio, and print media sources. In addition, information was available through Internet sites and social media Web sites including Wikipedia and Twitter.

The initial H1N1 outbreak caused a large increase in social media activity as people discussed their concerns ...