Does this mean we should nuke France and China?
Probably not. If the infection gets out from control, it will no doubt spread worldwide. They will get it also and it is unlikely they have any better vaccines than we do.
However, somebody possessing the weaponized disease will presumeably already have developed vaccines to protect themselves against their own weapon. That's why you have to annihilate them without hesitation while you are still able.
I don't think we can erect a %100 effective defense against an enemy that is determined to use bio-warfare so we have to make it clear in very unambiguous language to our enemies and their proxies that their destruction is assured if we are attacked with WMDs. I just hope that our leadership has the will to retaliate on a massive scale if we are hit.