Most reports about seasonal influenza cite an average of about 36,000 deaths in a typical season, but that number is too high and grossly misleading, the Centers for Disease Control and Prevention said Thursday.
The number of deaths in a given year depends on a variety of factors, including how long the flu season lasts, how many people get sick and who gets sick. But by far, the most important factor is the strain of flu that predominates in a given season.
When an H3N2 strain predominates, the number of deaths typically is about 2.7 times higher than in years when an H1N1 strain predominates. Researchers are not sure why that is, but it occurs at least in part because the H3N2 virus mutates more rapidly.http://articles.latimes.com/2010/aug/27/science/la-sci-flu-deaths-20100827