Before I moved to Oregon a year ago, I co-founded and ran a shelter in
Missouri.  In the course of five +/- years, we took in approximately 700
ferrets, 95% of whom were not vaccinated.  They all went to the vet for
their Fervac-D shots.  We never did pre-treatment.  Out of all those plus
personal ferrets I saw a grand total of three reactions (less than 1%).
Yes, it's really scary when it happens, but I don't think that figure of
1 in 1000 may be that far off.
 
I'd love to see posts from other shelter operators about their
experiences with reaction rates.
 
Sara & her four fuzzies
[Posted in FML issue 3970]