CDC: Influenza fatality rates vary widely

September 2, 2010

Between 1976 and 2007, the estimated number of deaths from influenza has ranged from a low of 3,300 to a high of nearly 49,000, according to a recent report from the Centers for Disease Control and Prevention.

These findings differ significantly from a previous, widely cited estimate of 36,000 annual influenza deaths.

The report found death rates are closely related to type of influenza. Seasons when influenza A (H3N2) viruses were prominent had 2.7 times higher death rates than in years when influenza A (H1N1) or B were more prominent.

Deaths reported were influenza-associated from respiratory and circulatory causes. About 90 percent of these deaths overall were individuals 65 and older.

The report noted that because influenza death estimates vary so widely based on age and influenza strain, death rates should not be presented as a single annual number.