Novel H1N1 Influenza
(referred to as "swine flu" early on) is a new influenza virus causing illness in people. On June 11, 2009, the World Health Organization (WHO) raised the worldwide pandemic alert level to Phase 6 in response to the ongoing global spread of the novel influenza A (H1N1) virus. A Phase 6 designation indicates that a global pandemic is underway.
Seasonal Influenza
is a contagious respiratory illness caused by influenza viruses. Seasonal influenza outbreaks occur every year.