H1N1 Flu

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.

Questions & Answers

2009 H1N1 Flu In The News

December 4, 2009 1:00 PM ET

Are antiviral drugs being used more often to treat severe flu illness during this pandemic than they have been for seasonal flu?

Yes. Significant increases in the proportion of hospitalized adults and children being treated with influenza antiviral drugs have been noted during the 2009 H1N1 pandemic compared to the proportion of adults and children that have been treated with flu antiviral drugs during past seasonal influenza epidemics. Data on influenza-associated hospitalizations collected through CDC’s Emerging Infections Program (EIP) during the 2009 H1N1 pandemic indicate that 80% of children admitted to the hospital with 2009 H1N1 were treated with antiviral drugs compared to less than 20% of hospitalized children treated with antiviral drugs during past seasonal influenza epidemics. Among hospitalized adults, the proportion treated with antiviral drugs has increased from approximately 50% to 80%. EIP conducts surveillance for laboratory-confirmed influenza-related hospitalizations in children and adults in 62 counties covering 13 metropolitan areas of 10 states. Antiviral treatment is recommended for all persons hospitalized with 2009 H1N1. CDC has additional information on antiviral drugs and recommendations on the use of antiviral drugs this flu season.