I see, but I am confused what the actual conflict is our characters face.
Will the problem be the fact that society is gone?
Will it be the illness that is still around? And if so, would our characters try to reach Israel? But you said that it was impossible to go there.
The 'zombies' would be a choice I would understand, but you said they were defeated now?
All I see right now is a cool story, but one we enter when it is already told. Unless I am misunderstanding things (which is more than possible, I'm quite tired at the moment)