Originally Posted by kurish

Even if the OP could get a new passport in 24 hours(!!), that option is out of the question because he'll still need the Brazilian visa from the old passport. (You did get that, right, DBoy?)

I don't understand why getting the yellow fever shot today is absolutely not possible. Find a clinic. They're out there. Miss a couple hours of work, or whatever. (But even this is still an issue, because the yellow fever shot takes ten days to become effective. So even if you do get a shot today, they could still deny you entry. Can't hurt though, and could help if you get a border control agent in a forgiving mood.)