Do you want a country that prohibits people from leaving when they want? So you can't require it on exit.
And the most basic right of citizenship is the ability to enter the country, so you can't require it on entry either.
All you can do is convince other countries to prohibit entry without vaccination,
I think it was a good idea. Too bad there's no vaccine against bot flies :(
Infants, the very old, and immunocompromised individuals in particular. Given that there's a large population of HIV-infected individuals in the San Francisco Bay Area, that last might be a significant public concern.
I've heard this is common among the anti-vax crowd. Not saying it is what happened in this case, just giving a personal anecdote.
These methods might not work for all universities, but I know they work for some.
The UK regularly seems small-scale measles outbreaks due to the same idiots.