The Centers for Disease Control and Prevention (CDC) developed a method to provide an estimated range of the total number of 2009 H1N1 cases, hospitalizations and deaths in the United States by age group using data on flu associated hospitalizations collected through CDC’s Emerging Infections Program. On November 12, 2009 CDC provided the first estimates for April through October 17, 2009 and committed to updating those estimates approximately monthly.

On December 10, 2009, CDC issued updated estimates for the numbers of 2009 H1N1 cases, hospitalizations and deaths in the United States since the pandemic started in April 2009 through November 14, 2009.
  • CDC estimates that between 34 million and 67 million cases of 2009 H1N1 occurred between April and November 14, 2009. The mid-level in this range is about 47 million people infected with 2009 H1N1.
  • CDC estimates that between about 154,000 and 303,000 2009 H1N1-related hospitalizations occurred between April and November 14, 2009. The mid-level in this range is about 213,000 H1N1-related hospitalizations.
  • CDC estimates that between about 7,070 and 13,930 2009 H1N1-related deaths occurred between April and November 14, 2009. The mid-level in this range is about 9,820 2009 H1N1-related deaths.


A table showing this data by age group is available. In addition, background information on these estimates and information about the methodology used to generate these estimates also is available on the CDC web site.