[Trust but Verify]

Smallpox would kill millions where? Good Lord, you'd have to infect, 50 million people to get a mortality in the millions. How are 50 million people going to get infected with anything before quarantines, etc would be put in place.

[eno_]

The death rate is about 30%. It would take a minimum of 6 million infections to reach a death rate of "millions." You also assume the epdemic does not spread to parts of the world where it cannot be controlled through quarantines.

[Tolerance Sucks Rocks]

I've read that smallpox kills a third of its victims. Therefore, if you expose all of New York to smallpox, for example, you could end up with up to 2.3 million or so dead.