Smallpox.
The mortality rate is 30% to 35%.
Serious side effects to vaccination affect about 1000 out of 1M people. Life-threatening side effects <50 out of 1M. Actual deaths some lower number.
http://www.bt.cdc.gov/agent/smallpox/vaccination/reactions-vacc-public.asp
Let’s assume a 30% infection rate and nobody vaccinated. Out of 1M people that’s 300,000 that contract the disease. Of that number we can expect about 30% to die, or roughly 100,000. A large percentage of the survivors will be crippled and/or horribly scarred. Up to date medical care in an ICU would probably significantly reduce both numbers. However, in a major epidemic these available resources will be utterly swamped and can provide treatment to only a tiny fraction of those who need them, especially since the medical staff themselves are as affected as anybody else, perhaps more due to a greater likelihood of exposure.
So that’s perhaps 150,000 or more out of 1M either dead or severely affected with no vaccination.
With the 1M vaccinated there will be about 1000 severely affected.
My posts have been about vaccination in general, not about the “swine flu” vaccination in general. It is entirely possible that scientists and doctors are attempting to apply the smallpox vaccination experience to diseases where it is not appropriate.
It is also a fact that roughly 50,000 people die each year in USA from the “regular” flu. I saw a newspaper yesterday that claimed ~500 deaths from April thru October for the “swine flu.” Didn’t read the article, but the headline implied that this death rate was unprecedented.
I suspect a headline reading, “So Far Swine Flu No Big Deal” would not sell many papers. This may have played a role in the editor’s decision on how to word the headline. :)