The government has bigger guns. And tanks, and chemical weapons, and nukes. It might even become necessary to nuke a whole city in order to save the rest of the world.
The government can draft you and force you to fight a war, and it can execute you for a crime, of course they can vaccinate you against your will if it's an emergency.
you have been watching to many resident evil and outbreak movies. That will NEVER happen. Look at the SARS responce, way to rapid for full quarentine to be effective except in countries like Australia (we didnt have a single case) so what possible reason would there be to nuke a city? its just not going to happen, its stupid to even suggest it. Look at the responce to the spanish flu for Christ sake.
Disaster managment plans are designed mainly to deal with natural disasters. Ie the pisspoor job of managing the evacuation center at the superdome (or whatever it is called) in New orleans. Yes health events fall under its scope but there is no possible potentual reason to use nukes.