On Sat, 19 Oct 1996, David J. Ellis wrote:
>Jeff Johnston explained some of the vaccination reactions.  I would like to
>seek an opinion on a couple of things related to vaccination reactions.
 
David--the late reaction following a Fervac-D vaccination you describe
occurred *too* late to be considered an anaphylactic reaction.  Anaphylaxis
is part of an immune response called Type I "hypersensitivity", which occurs
*very* shortly after exposure, sometimes within seconds, but usually within
the first hour after exposure.
 
The reaction you describe of shaking, vomiting and trouble breathing--all
occurring about 48 hours after exposure sounds more like a delayed
hypersentivity reactions (called "Type IV hypersensitivity") or perhaps
something else entirely, such as a blockage or a particularly bad flu-like
response to the live vaccine.  (Delayed hypersensitivity produces the sort
of reaction seen with tuberculin skin tests, which take a few days to show
up.) If this *had* been a type-IV reaction, benedryl wouldn't have done much
good because type-IV reactions are not caused by mast cells, which produce
histamine (benedryl is an antihistamine), but by T cells--the assassins of
the immune system that identify infected cells and kill them.  Something
that would blunt cell-mediated immunity would be useful to lessen such a
reaction.  I don't suppose your vet took a blood sample and checked for IgE
levels (an indication of type-I reactions)?
 
>She's due for her rabies shot as soon as she recovers enough.  I'm told by
>my vet that often there is a lesser reaction the second time round than
>there was the first time she reacted.
 
I'd kinda think all bets are off on this one.  I imagine your vet's talking
about typical immediate reactions.  This delayed reaction (if that's what it
was) is *not* typical.  If you want to try vaccinating her again when she's
up to it, you might consider premedicating with benedryl again but tell the
vet you want to be able to administer corticosteroids and/or epinephrine at
home if necessary and be sure to get good instruction for administering
these.  Epinephrine can be dangerous in too big of a dose.
 
>This will be her third Imrab. The first gave no reaction ...
 
That's what you'd expect of allergic reactions.  The first exposure is the
one that sensitizes the animal to the antigen.  Given the amount of time
expired following vaccination, this is not a typical "type-I" reaction.
It's either a delayed reaction or something else.  If it's something else,
you may want to try again.  If it's a delayed reaction, remember, the
benedryl won't do much good.  One thing that isn't proven but is worth a try
is to give your ferret the contents of a small-dose vitamin E capsule (say,
100 IU) a few days before the injection.  Vitamin E in large doses
suppresses inflammatory responses (also suppresses vitamin K and clotting,
so, warn your vet if blood is taken for any reason).  It may help blunt any
reaction.  Vitamin E is also fairly non-toxic, too, so 100 IU once every few
months shouldn't hurt.
 
Good luck, --Jeff Johnston
[Posted in FML issue 1727]