What is the 2009 H1N1 influenza virus?
The 2009 H1N1 influenza virus is a subtype of influenza virus type A. It causes respiratory illness in some individuals infected with the virus. It is a new virus that has never before circulated among humans. It is not related to previous or current human seasonal influenza viruses. Like seasonal flu, disease caused by the 2009 H1N1 influenza virus in humans can vary in severity from mild to severe. The Centers for Disease Control and Prevention (CDC) has determined that this virus, which was first identified in Spring 2009, is contagious and is spreading from person to person. In mid-June 2009, the World Health Organization (WHO) reported cases of infection with the virus in more than 70 countries and declared it a phase 6 pandemic. The WHO reported that as of November 1, 2009, worldwide more than 199 countries have reported confirmed cases of 2009 H1N1 pandemic influenza, including over 6000 deaths.
