>With the violent reactions to vaccinations that I've read about lately,
>should I still vaccinate them and risk them reacting?
Basic Statistics and Perceived Risks
I know other people will stress the importance of vaccination with very few
exceptions, but the question got me a little curious. I went to the FML
archives and did a search on the word 'reaction' for the time January 1,
1999 to July 2, 1999. I got 135 hits, so it took me a few minutes to scan
through the synopsis that is provided, and this is what I found for the
SAMPLE SIX MONTH PERIOD. Please note that I may have missed a few since
some reactions might not have appeared with my search parameters (i.e.
'reaction' misspelled, or the word not used).
REACTIONS (Including vomitting, extreme lethargy, comas(0), death(0) ): 6
RESPONSES (More vague indications including lumps, itching, mild
lethargy, uncertain symptoms, possible placebo effects): 6
MEMORIES (ie 'Once upon a time I had a ferret who reacted...') : 10
QUESTIONS & COMMENTS: Lots and lots and lots
SAMPLE SIZE ASSUMPTION: 12,000
(Number of readers=3000, Estimated average number of ferrets per reader=4)
Extrapolating out the numbers to a one year time period we should see
approximately 12 severe reactions per 12,000 ferrets per year REPORTED ON
THE FML, and a similar number of responses. Two vaccinations per ferret
per year (1 rabies & 1 distemper) brings the total number of vaccinations
up to 24,000. The percentage of FML REPORTED major reactions is then 0.05%
or 1 in 2000 chance. The percentage for minor responses is the same.
The word 'reaction' received 135 hits for the 6 month period, about half
of which were questions, or comments about reactions and some were stories
about past reactions (sometimes the same person posted about the same
incident multiple times). The other half just happened to have the word
'reaction' in the text. Most of the hits were chains of posts in response
to a particiular incident or question. I estimate that on average there
are about 2 or 3 posts about vaccine reactions per week (lumped into
clusters of course).
The point that I want to make from this little exercise is that a
misconception can easily be PERCEIVED from the FML about occurences.
Although we keep reading about vaccine reactions, the number of reactions
is actually quite low, and the vaccines may be much safer than one might
expect simply from reading the FML. The only reasonable way to get a good
feeling for the safety is to examine the records for a good cross section
of many vets from across the country. A single vet's records can not be
used, since a luck, single bad batch of vaccine/ringer solution, or poor
technique could skew the results.
Disclaimer: The preceeding has been what is often referred to as 'Back of
the Envelope' engineering. It is NOT suitable for peer review publication,
but it can be useful for getting a basic grasp of a problem or equation,
and may be helpful in determining whether a full study is warranted.
P.S. My feeling is that one of the best reasons to vaccinate is to protect
your pet from legal action or automatic rabies testing. Another opinion is
that the only times to NOT vaccinate your pet are (1) if there has been a
strong reaction previously AND pretreating has had little or no effect ; or
(2) the animals immune system has been severely compromised from an
unrelated illness or event.
--
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Bryan P. Coffey - Sudbury, MA
[log in to unmask]
http://www.gis.net/~bpcoffey
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Weasel Warriors - Albi, Esef, Merri, and Mint
http://www.gis.net/~bpcoffey/furball.html
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[Posted in FML issue 2991]
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