Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated.
- The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide.
- The English language content on this website is being archived for historic and reference purposes only.
- For current, updated information on seasonal flu, including information about H1N1, see the CDC Seasonal Flu website.
Site last updated August 11, 2010 1:00 PM ET
The U.S. Public Health Emergency for 2009 H1N1 Influenza expired on June 23, 2010. On August 10, 2010, the World Health Organization (WHO) International Health Regulations (IHR) Emergency Committee declared an end to the 2009 H1N1 pandemic globally. For information about CDC’s response to the 2009 H1N1 pandemic, visit The 2009 H1N1 Pandemic: Summary Highlights, April 2009-April 2010. Internationally, 2009 H1N1 viruses and seasonal influenza viruses are co-circulating in many parts of the world. It is likely that the 2009 H1N1 virus will continue to spread for years to come, like a regular seasonal influenza virus.
See More on Past H1N1 Updates »
CDC recommends a yearly flu vaccination as the first and most important step in protecting against the flu. The U.S. 2010-2011 seasonal influenza vaccine will protect against an H3N2 virus, an influenza B virus, and the 2009 H1N1 virus that emerged last year to cause the first global pandemic in more than 40 years and resulted in substantial illness, hospitalizations and deaths. Seasonal 2010-11 vaccine has begun shipping from manufacturers and CDC recommends that everyone 6 months and older get a 2010-2011 flu vaccine for the upcoming season as vaccine is available.
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