These numbers represent a middle range in CDC estimates. The actual number of swine flu cases could be as low as 39 million and as high as 80 million cases during this time period, government officials say.
- Between 173,000 and 362,000 Americans were hospitalized with H1N1 flu between April and mid-December.
- Between 7,880 and 16,460 H1N1-related deaths occurred.
- Roughly 1,200 children and teens, 8,600 adults under age 65, and 1,300 adults over 65 died from H1N1.
The figures were reported Friday in the CDC's Morbidity and Mortality Weekly Report.
The report also included new figures on H1N1 vaccination coverage in the U.S. between October 2009, when the first vaccines became available, and December 2009.
By the end of December, an estimated 61 million people, or roughly 20% of the U.S. population, had been vaccinated.
Slightly less than one in three people in the initial target group received the vaccine. This included pregnant women, people living in households with babies under 6 months of age, children and adults ages 6 months to 24 years, and older adults with certain health conditions.
An estimated 29% of children and teens between the ages of 6 months and 18 years were vaccinated.
There is now plenty of vaccine, and the CDC's Advisory Committee on Immunization Practices (ACIP) now has no restrictions on who should be vaccinated.
"Now that there is ample supply of vaccine, efforts should continue to improve vaccination coverage among persons in the initial target groups, as well as to offer vaccination to the rest of the U.S. population including those aged 65 and over," the report states.
Influenza activity has declined in the U.S. in recent weeks, but the report notes that cases of H1N1 flu, including life-threatening cases, are still occurring.
Among people who had not yet been vaccinated who responded to a survey conducted between Dec. 27, 2009, and Jan. 2, 2010, 11% said they definitely intended to be vaccinated and 22% said they probably would be vaccinated.
"The epidemiology of H1N1 influenza over the months ahead is unknown, but another rise in incidence, as occurred during the winter of the 1957-1958 pandemic, remains possible," the report notes. "Vaccination remains the best way to prevent influenza infection and influenza-related hospitalizations and deaths."