Some people suspect that if a national health crisis were to occur, that a vaccine could be made mandatory. (I hope that President Obama doesn't read my website, because I'd hate to give him any ideas ? he gets so excited about circumventing Congress and making his own laws.)  He's already signed an executive order that says people suspected of being ill can be detained and isolated. Michael Snyder of The Economic Collapse Blog wrote:

"Isolation" would not be a voluntary thing.  The federal government would start hunting down anyone that they "reasonably believed to be infected with a communicable disease" and taking them to the facilities where other patients were being held.  It wouldn't matter if you were entirely convinced that you were 100% healthy.  If the government wanted to take you in, you would have no rights in that situation.  In fact, federal law would allow the government to detain you "for such time and in such manner as may be reasonably necessary".