IMRAB 3 is the right vaccine but it has NOT been tested for being longer lasting than a year in ferrets, so *no one* knows how long it does last in them beyond a year. As a result it is an annual vax in them. There can be a LOT of variation across species lines in how long vax last and titer levels are *not* firmly known. Here is the info you need, complete with time factor in the chart: http://www.avma.org/pubhlth/rabcont.asp [Posted in FML issue 4644]