I recently had a very bad scare with my Joey as well.  When he was a kit,
2 years ago, he had a very bad reaction to his third shot of the series.
Well, the vet had given rabies at the same time and she attributed the
reaction to that.  Last year, Joey was pretreated with benadryl for 15
minutes before his shot and was completely fine.  This year, he was
pretreated again, and we nearly lost him.  I'll never get another
ferretvac-d distemper for Joey again.  I'm considering trying the newest
shot, but I'm not sure yet.  The vet went so far as to say she wouldn't
give him the rabies either, but I've never heard of a ferret having a
reaction to rabies by itself.  As a side note, this particular vet (for
the last shot) isn't very ferret knowledgable.  I plan to switch vets
soon.
 
As far as "needing" the shots, if your ferret never comes in contact with
any other animals that *could* carry the distemper virus, then they don't
really need the shot as far as I know.  The thing is, you never know for
sure what is going to happen with ferrets.  He might sneak out the door
one day and come across a dog that is carrying distemper.  I think (but I
don't know for sure) that distemper can be carried on clothing or skin, so
you might bring it home unknowingly.
 
Extreme caution should be used with your fuzzy if you elect not to give
him any more shots.  Keep in mind that there are (at least) three
different brands of distemper out there for ferrets now.  If he reacted
to one, he might not react to one of the others.
 
Natalie and the furry snakes
Katie, Lyssa, and Joey
Angeled: Mittens
[Posted in FML issue 3679]