If BIG is going to give us one last shot at the vaccine debacle, let me try
to get back to the scientific and biostatistical realities.  If this goes
over anyone's head, send me an e-mail directly and I'll try to explain
things in simpler terms.
 
First: The results of the vaccine survey that Howard Davis described
definitely tell us that severe reactions *do* occur with *all three*
distemper vaccines.
 
Second: Whether Fervac causes more severe reactions than the other two
vaccines cannot be determined with the data presented.  Comparisons have
been made using three "groups" of ferrets--each group consisting of reports
of ferrets receiving a particular vaccine.  Unfortunately, these groups are
not comparable statistically for multiple reasons.  (E.g.: Far more ferrets
nationwide receive Fervac because it is the only approved vaccine thus the
rate of observed reactions must be adjusted for this.  The vaccine
administered at a young age at the breeder must be taken into account.
Simultaneous vaccination with Imrab-3 must be factored in.  Some ferrets
have been injected with more than one type of vaccine, and thus belong to
several groups.)
 
Third: The discussion of minor reactions are not scientifically valid.  The
ability to recall minor reactions is notoriously poor, and reactions such as
stinging or scratching at the injection site can be caused by the needle
stick alone, by the vehicle in which the vaccine is suspended, or by
localized pressure where the vaccine was injected.  And to totally confuse
everyone, the development of lethargy after vaccination may even be a *good*
sign.  This means the attenuated virus has gotten to the ferret's immune
system and that a strong immune response can be expected.
 
OK, parable time.  Back in the '60s, some researchers in Scandanavia
examined the medical records of women committed to mental institutions to
see if any exposure in the hospital affected their health.  A drug called
reserpine was strongly linked with increased risk of breast cancer.  As we
know now, breast cancer is associated with the duration of estrogen
exposure, so that women who never have children or are never on the pill
(which chemically mimics preganancy) have higher rates.  Of course, women in
mental institutions were much less likely to ever have children or be on the
pill.  The drug didn't cause breast cancer after all.  It was a coincidence
due to the population of people chosen for study.
 
We may have the same thing here *or* we may have a real effect on our hands.
We know reactions occur with all three vaccines.  Because of the way the
survey data were collected, we cannot yet tell if any one vaccine is
associated with a greater risk of severe reactions.  I am willing to look at
the survey data and reanalyze it, if possible, or to help design a
epidemiologic study to find a valid answer.  I have no interest in seeing
one vaccine maker succeed over another, nor do I believe that any one
vaccine is better or worse than the other.  At this point, scientifically,
we simply do not know that.
 
--Jeff Johnston  ([log in to unmask])
[Posted in FML issue 1542]