The people who usually die from the general "flu" season are the ones with weak immune systems, such as the eldery or very young. They die because they are already more susceptible to secondary infection from bacteria. The difference with the swine flu is that the fatalities are generally people who are the healthiest of the population-- those between 12-40 years of age.
This swine flu is more comparable to the 1918 flu, which targeted healthy people. The more robust your immune system, the more likely you were going to die from it! The 918 flu, which had similar origins to the present swine flu, took over a person's immune system and used it as a machine to replicate more virus.
Also, the % who die from swine flu is much higher than the % of people who die from regular flu. 159 deaths in Mexico out of 1100 infected =14.5% fatality rate. That means 4.26 mil people may die if everyone got it!
at 10:17 PM on Apr. 30, 2009