Okay, first rule of thumb: whenever a pet gets a vaccine ALWAYS wait in the veterinary office for at least 45 minutes. Waiting much longer is better since pets can not tell you is an eye is starting to get itchy, if a hidden hive may be present, if swallowing is becoming difficult, or if other early signs of a reaction are happening. (This is the same reason allergists have people wait 20 minutes in their offices after allergy shots.) Not being able to get immediate veterinary care can reduce the chances of good outcome, but fortunately, ferrets do usually survive these anaphylactic allergic reactions. Since both shots were given in the same visits you are stuck in the situation where you don't know which vaccine the ferrets reacted to. It's usually the CDV one, but not always. For that reason it is almost always advised that the shots be given at separate times, and to reduce the challenge the ferret is facing it is almost always advised that those visits be separated by at least two weeks. It is also usually recommended that ferrets be pre-treated with Benedryl. Some vets prefer their clients to do this ahead of time, while other vets prefer to give a Benedryl shot themselves beforehand. The new Merial Purevax ferret canine distemper vaccine has in field uses as well as the pre-release studies shown itself to have a greatly reduced risk of causing life-threatening allergic reactions. Yes, some still do react; that is true or anything. Some people die if they eat common foods, or get commonly taken medications due to such reactions. The reduction in risk is far better for ferrets, though. It also is important that folks do their best to make this economically a worthwhile venture by Merial to encourage further medical improvements for ferrets. [Posted in FML issue 3873]