Influenza killed an average of 23,607 people each year in the past three decades, one-third fewer than the 36,000 estimate previously used to weigh the severity of a flu season, a U.S. study found.
The 36,000 figure, cited in media stories during last year's swine flu pandemic, was based on a 2003 report that examined data from the 1990s. That was a particularly deadly decade for flu strains and the resulting estimate overstated the impact, according to the study by the U.S. Centers for Disease Control and Prevention. The research reported Thursday looked at data from 1976 to 2007.
Influenza is a rapidly evolving virus, and the severity of the season depends on which strains are circulating and how well a population has been inoculated. Annual deaths ranged from 3,349 to 48,614 in the study. The H1N1 strain that emerged last year killed 13,000 people. The impact on children and young adults was greater than in a typical season. - Bloomberg News