That is a good question. How long does the distemper vaccine last in ferrets? We simply do not know the answer to that question. A duration of immunity study would have to be done. Basically this means ferrets would have to be vaccinated then monitored for titers and challenged frequently for years. The vaccine companies are not likely to foot the bill for this. That means a vet school or research center would have to do this, but it has not been done as of yet. Since distemper is almost 100% fatal, I would not take any chances. The same with rabies. It is a fatal disease. Plus an unvaccinated ferret will likely get the death penalty if it bites or scratches someone and is reported. BTW-I get my rabies vaccine every 2 years! The human vaccine cost $50 a dose. Jerry Murray, DVM [Posted in FML issue 3423]