Another answer given in FML that needs to be in both archives so am carrying to the FHL... IMRAB 3 is rated for 3 years in some animals that it has been TESTED in for three years of effectiveness (which is why "3" is in the name and that often causes confusion). Ferrets have NOT been tested on that score so it is considered to be effective for ONE YEAR, POSSIBLY more but how much more remains unknown. Vaccines do NOT always behave the same in different species. Example: When rabies vaccines were first being tested starting back in about 1988 or so in ferrets one of the OTHER vaccines that worked a more than one year in some other species provided only 6 months of protection for ferrets. After 6 months when they were challenged with rabies virus they were able to contract rabies. (It took 10 years to get from that point to having many ferret lives saved by improvements in the compendium after thorough CDC work on rabies in ferrets had been completed. This year is the 10th anniversary of that success being enacted in the U.S. for the ferret community.) Rabies info: http://www.nasphv.org/ (National Association of State Public Health Veterinarians) Here is the latest (Dec 2007 and it will being the Jan 2008 JAVMA (Journal of the American Medical Veterinary Association) Compendium of Animal Rabies Control and Prevention: http://www.nasphv.org/Documents/RabiesCompendium.pdf People will want to know that rabbits and beavers have been joining groundhogs as too often unexpected rabies vectors that are increasing. The first two are rare vector animals but ground hogs have been known to be among the vector animals for some time now. Notice in Section III for IMRAB 3: >Ferrets 1 ml 3 months Annually SC which is species, dose, age of first vaccination, how often to repeat, how to give the vaccine. Ferrets are NOT considered to be vaccinated if more than a year has passed. The animals for which IMRAB 3 is 3 year vaccine are dogs, cats and sheep. Cattle , horses, and ferrets need it each year. More rabies info: http://www.avma.org/issues/policy/rabies_control.asp (Guidelines for ordinances) http://www.cdc.gov/rabies/ (Loads of info at many different reading levels; even good ones as resources for a kid's school composition) http://www.microbiologybytes.com/virology/bushmeat/bush4.html http://www.vaccineinformation.org/rabies/qandadis.asp http://www.lawrencefire.com/safety_tips/rabies/rabies.asp This is not the first time that the "3" in the name of IMRAB 3 has caused some confusion and it won't be the last... I am a bit surprised that any non-expired Fervac-D was found to vaccinate your ferret. United stopped making it. Usually people use Purevax which does have a lower rate of reactions in testing that was done both in lab and clinics and which is fully tested for use in ferrets, or Galaxy-D (not fully tested in ferrets, though there was one short (21 days if memory serves) test of a few male kits, and the vaccine which was its "parent", Frome- D (spelling ? since it has been a long time) was tested in ferrets though Galaxy is NOT the same vaccine). This is another case of some useful info for all so carrying it to two lists; now if only I'd gotten both addies right the first time... Sukie (not a vet) Recommended ferret health links: http://pets.groups.yahoo.com/group/ferrethealth/ http://ferrethealth.org/archive/ http://www.afip.org/ferrets/index.html http://www.miamiferret.org/fhc/ http://www.ferretcongress.org/ http://www.trifl.org/index.shtml http://homepage.mac.com/sukie/sukiesferretlinks.html [Posted in FML 6020]