You've just opened a big black hole with many cans of worms.
Now, are you talking about Avian Flu - H5N1 - or do you refer to a Human Flu Pandemic for which there is no current vaccine?
I wonder how many aircrew will be prepared to fly to a destination where flu is at pandemic levels and causing fatalities amidst persons of their age group.
There was a rumour that one island in the Southern Hemisphere would literally close its borders.
Wonder what draconian actions governments around the world will take?
Tamiflu needs to be taken continuously - will stocks last? After effects on those that take it? Hope drowsiness is not one of them!