Sure, I'd be glad to do that. Thanks for the question.
I think Dr. Spika is probably in a better position to speak to some of these questions.
An epidemic is an increase in the number of cases of a given illness in a particular location. We call it a pandemic when it's pretty much global in nature, when the epidemic is occurring everywhere. That's the basic difference in terms of epidemiologic definitions.
The connotation of the word “pandemic” has come to mean a very severe influenza outbreak, as in 1918, but that is not really the definition of what a pandemic is. It doesn't necessarily have to be severe. To my mind, that's the origin of some of the criticisms of the WHO and others as to making the call about a pandemic, because it wasn't as severe as it might have been and it certainly wasn't as severe as the one in 1918.
I would refer the rest of the question to Dr. Spika or the other witnesses.