If you don't like American freedom you're free to leave, assuming you do live here. I would hope so since any foreigner would have even less of a foot to stand on telling us what to do.
The Constitution does not mention vaccines in any section of it.
ParanoidObsessive posted...
Ehh, modern humans (ie, homo sapiens) have existed since before the last glacial period reached its maximum, and even before that hominid species in general that technically count as "human" (Neanderthal, Cro Magnon, etc) were around. Obviously there isn't going to be anything popping out of the ice cap or Antarctica (unless Lovecraft was right), but there are plenty of places where tundra and permafrost has trapped relatively recent corpses that are starting to defrost. So something might still slip out that's ready to hop to humans.
And being different now isn't necessarily a positive - it can go hand-in-hand with humans having lost general immunity to diseases we used to possess. The majority of modern diseases stem from prolonged human/animal contact deriving from domestication, which means few pre-date agriculture/herding... but if something's been out of circulation for a while it might hit us harder than it would have millennia ago.
Bacteria is definitely an issue (anthrax being a common fear), but it's not the only issue.